LoongArch: Drop unused parse_r and parse_v macros

When building with CONFIG_LTO_CLANG_FULL, there are several errors due
to the way that parse_r is defined with an __asm__ statement in a
header:

  ld.lld: error: ld-temp.o <inline asm>:105:1: macro 'parse_r' is already defined
  .macro  parse_r var r
  ^

This was an issue for arch/mips as well, which was resolved by commit
67512a8c ("MIPS: Avoid macro redefinitions").

However, parse_r is unused in arch/loongarch after commit 83d8b389
("LoongArch: Simplify the invtlb wrappers"), so doing the same change
does not make much sense now. Just remove parse_r (and parse_v, which
is also unused) to resolve the redefinition error. If it needs to be
brought back due to an actual use, it should be brought back with the
same changes as the aforementioned arch/mips commit.

Closes: https://github.com/ClangBuiltLinux/linux/issues/1924


Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>