RISC-V: Fix vmnot asm check (Should check vmnot.m instead of vmnot.mm)

RISC-V: Fix vmnot asm check (Should check vmnot.m instead of vmnot.mm)

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/base/binop_vx_constraint-148.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-149.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-150.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-151.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-152.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-153.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-156.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-157.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-159.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-160.c: Change vmnot.mm to vmnot.m.
	* gcc.target/riscv/rvv/base/binop_vx_constraint-161.c: Change vmnot.mm to vmnot.m.