[MC][LoongArch] Fix needsRelocateWithSymbol() implementation

LoongArch should be `section plus offset`, so use the generic implementation
of `llvm/lib/MC/MCELFObjectTargetWriter.cpp` to return `false` directly, like
x86 and aarch64.

```
$ cat test.c
static int __attribute__((section(".text.another"))) test(int a, int b)
{
	return a + b;
}
static int a = 1, b = 2;

int foo()
{
	test(a, b);
	return 0;
}

$ gcc -c test.c
$ readelf -Wr test.o

Relocation section '.rela.text' at offset 0x2a0 contains 5 entries:
    Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
0000000000000010  0000000300000047 R_LARCH_PCALA_HI20     0000000000000000 .data + 0
0000000000000014  0000000300000048 R_LARCH_PCALA_LO12     0000000000000000 .data + 0
0000000000000018  0000000300000047 R_LARCH_PCALA_HI20     0000000000000000 .data + 4
000000000000001c  0000000300000048 R_LARCH_PCALA_LO12     0000000000000000 .data + 4
0000000000000028  0000000500000042 R_LARCH_B26            0000000000000000 .text.another + 0

Relocation section '.rela.eh_frame' at offset 0x318 contains 2 entries:
    Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
000000000000001c  0000000500000063 R_LARCH_32_PCREL       0000000000000000 .text.another + 0
000000000000003c  0000000200000063 R_LARCH_32_PCREL       0000000000000000 .text + 0
```

Reviewed By: SixWeining, MaskRay

Differential Revision: https://reviews.llvm.org/D137384

llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchELFObjectWriter.cpp

@@ -24,13 +24,6 @@ class LoongArchELFObjectWriter : public MCELFObjectTargetWriter {
 
   ~LoongArchELFObjectWriter() override;
 
-  // Return true if the given relocation must be with a symbol rather than
-  // section plus offset.
-  bool needsRelocateWithSymbol(const MCSymbol &Sym,
-                               unsigned Type) const override {
-    return true;
-  }
-
 protected:
   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
                         const MCFixup &Fixup, bool IsPCRel) const override;

llvm/test/MC/LoongArch/Relocations/fde-reloc.s

@@ -10,5 +10,5 @@ func:
  .cfi_endproc
 
 # CHECK:   Section (4) .rela.eh_frame {
-# CHECK-NEXT:   0x1C R_LARCH_32_PCREL - 0x0
+# CHECK-NEXT:   0x1C R_LARCH_32_PCREL .text 0x0
 # CHECK-NEXT: }