LoongArch: Fix predicate for symbolic_pcrel_offset_operand.

The predicate checks if the operand is PLUS(symbol_ref, const_int), but
the match (match_operand 0/1) is not equal XEXP(op, 0/1). It should be
adjusted to use match_test and pass XEXP(op, 0/1) into the constraint
function.

gcc/ChangeLog:

	* config/loongarch/predicates.md: Update ops.

Author: zhaozhou

gcc/config/loongarch/predicates.md

@@ -575,8 +575,8 @@
 
 (define_predicate "symbolic_pcrel_offset_operand"
   (and (match_code "plus")
-       (match_operand 0 "symbolic_pcrel_operand")
-       (match_operand 1 "const_int_operand")))
+       (match_test "symbolic_pcrel_operand (XEXP (op, 0), mode)")
+       (match_test "const_int_operand (XEXP (op, 1), mode)")))
 
 (define_predicate "mem_simple_ldst_operand"
   (match_code "mem")