add support for YT8512 phy

[freakishness]

Summary

Add support for YT8512C / YT8512H (10/100 Mbps Ethernet phy)

Impact

None

Testing

Test on imxrt board(mimxrt1062)

[xiaoxiang781216]

@freakishness could you fix the follow warn:

Error: /home/runner/work/nuttx/nuttx/nuttx/arch/arm/src/imxrt/imxrt_enet.c:1898:1: error: Blank line contains whitespace
Error: /home/runner/work/nuttx/nuttx/nuttx/arch/arm/src/imxrt/imxrt_enet.c:2441:83: error: Long line found
Error: /home/runner/work/nuttx/nuttx/nuttx/arch/arm/src/imxrt/imxrt_enet.c:2445:83: error: Long line found
Error: /home/runner/work/nuttx/nuttx/nuttx/arch/arm/src/imxrt/imxrt_enet.c:2449:83: error: Long line found
Error: /home/runner/work/nuttx/nuttx/nuttx/arch/arm/src/imxrt/imxrt_enet.c:2453:83: error: Long line found
Error: /home/runner/work/nuttx/nuttx/nuttx/arch/arm/src/imxrt/imxrt_enet.c:2455:66: error: Dangling whitespace at the end of line
Error: /home/runner/work/nuttx/nuttx/nuttx/include/nuttx/net/mii.h:1:77: error: Block comments have different lengths
Error: /home/runner/work/nuttx/nuttx/nuttx/include/nuttx/net/mii.h:873:76: error: Block comments have different lengths
Error: /home/runner/work/nuttx/nuttx/nuttx/include/nuttx/net/mii.h:880:1: error: Missing blank line after comment
Error: /home/runner/work/nuttx/nuttx/nuttx/include/nuttx/net/mii.h:891:1: error: Missing blank line after comment
Error: /home/runner/work/nuttx/nuttx/nuttx/include/nuttx/net/mii.h:892:1: error: Missing blank line after comment

[xiaoxiang781216]

@freakishness please rebase and sqaush your patch into one.

[freakishness]

@xiaoxiang781216 Sorry about that. I lost my github 2fa key.
I also have learned how to check source format use 'checkpatch.sh'.

[xiaoxiang781216]

@xiaoxiang781216 Sorry about that. I lost my github 2fa key. I also have learned how to check source format use 'checkpatch.sh'.

Ok, I squash your patch, please take a look.