RISC-V: Fix ICE on riscv_gpr_save_operation_p [PR95683]

RISC-V: Fix ICE on riscv_gpr_save_operation_p [PR95683]

 - riscv_gpr_save_operation_p might try to match parallel on other
   patterns like inline asm pattern, and then it might trigger ther
   assertion checking there, so we could trun it into a early exit check.

gcc/ChangeLog:

	PR target/95683
	* config/riscv/riscv.c (riscv_gpr_save_operation_p): Remove
	assertion and turn it into a early exit check.

gcc/testsuite/ChangeLog

	PR target/95683
	* gcc.target/riscv/pr95683.c: New.