Makefile: add missing ggml-quants-k.o to server target

[Efruit]

Current versions are unable to build server since ggml-quants-k came in to being, resulting build failures similar to the following:

/usr/bin/ld: ggml.o: in function `ggml_quantize_chunk':
ggml.c:(.text+0x27c0b): undefined reference to `ggml_quantize_q2_k'
/usr/bin/ld: ggml.c:(.text+0x27c3b): undefined reference to `ggml_quantize_q3_k'
/usr/bin/ld: ggml.c:(.text+0x27c6f): undefined reference to `ggml_quantize_q4_k'
/usr/bin/ld: ggml.c:(.text+0x27cae): undefined reference to `ggml_quantize_q5_k'
/usr/bin/ld: ggml.c:(.text+0x27cea): undefined reference to `ggml_quantize_q6_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x1e0): undefined reference to `dequantize_row_q2_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x1e8): undefined reference to `quantize_row_q2_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x1f0): undefined reference to `quantize_row_q2_k_reference'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x1f8): undefined reference to `quantize_row_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x200): undefined reference to `ggml_vec_dot_q2_k_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x210): undefined reference to `dequantize_row_q3_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x218): undefined reference to `quantize_row_q3_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x220): undefined reference to `quantize_row_q3_k_reference'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x228): undefined reference to `quantize_row_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x230): undefined reference to `ggml_vec_dot_q3_k_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x240): undefined reference to `dequantize_row_q4_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x248): undefined reference to `quantize_row_q4_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x250): undefined reference to `quantize_row_q4_k_reference'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x258): undefined reference to `quantize_row_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x260): undefined reference to `ggml_vec_dot_q4_k_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x270): undefined reference to `dequantize_row_q5_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x278): undefined reference to `quantize_row_q5_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x280): undefined reference to `quantize_row_q5_k_reference'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x288): undefined reference to `quantize_row_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x290): undefined reference to `ggml_vec_dot_q5_k_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x2a0): undefined reference to `dequantize_row_q6_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x2a8): undefined reference to `quantize_row_q6_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x2b0): undefined reference to `quantize_row_q6_k_reference'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x2b8): undefined reference to `quantize_row_q8_k'
/usr/bin/ld: ggml.o:(.data.rel.ro+0x2c0): undefined reference to `ggml_vec_dot_q6_k_q8_k'
collect2: error: ld returned 1 exit status

This patch adds the missing dependency, resolving the build failure.