LoongArch: Disable TLS type symbols from generating non-zero offsets.

TLS gd ld and ie type symbols will generate corresponding GOT entries,
so non-zero offsets cannot be generated.
The address of TLS le type symbol+addend is not implemented in binutils,
so non-zero offset is not generated here for the time being.

gcc/ChangeLog:

	* config/loongarch/loongarch.cc (loongarch_symbolic_constant_p):
	For symbols of type tls, non-zero Offset is not generated.