LoongArch: gas: add support using constant variable in instructions.
Instructions that can load immediate support using constant
variable like ".equ var, 123 li.w/d resgister, var".
gas/
* config/loongarch-parse.y
* config/tc-loongarch.c
Add four testcases.One is a program using constant variable,
one test using label is unsupported, and another two test
almost instructions that can load immediate.
gas/
* testsuite/gas/loongarch/li.d
* testsuite/gas/loongarch/li.s
* testsuite/gas/loongarch/imm_ins_label-fail.d
* testsuite/gas/loongarch/imm_ins_label-fail.l
* testsuite/gas/loongarch/imm_ins_label-fail.s
* testsuite/gas/loongarch/imm_ins.d
* testsuite/gas/loongarch/imm_ins.s
* testsuite/gas/loongarch/imm_ins_32.d
* testsuite/gas/loongarch/imm_ins_32.s
11 files changed
