LoongArch: Enable explicit reloc for extreme TLS GD/LD with -mexplicit-relocs=auto.

LoongArch: Enable explicit reloc for extreme TLS GD/LD with -mexplicit-relocs=auto.

Binutils does not support relaxation using four instructions to obtain
symbol addresses

gcc/ChangeLog:

	* config/loongarch/loongarch.cc (loongarch_explicit_relocs_p):
	When the code model of the symbol is extreme and -mexplicit-relocs=auto,
	the macro instruction loading symbol address is not applicable.
	(loongarch_call_tls_get_addr): Adjust code.
	(loongarch_legitimize_tls_address): Likewise.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/explicit-relocs-extreme-auto-tls-ld-gd.c: New test.
	* gcc.target/loongarch/explicit-relocs-medium-auto-tls-ld-gd.c: New test.