RISC-V: Support integer FMA/FNMA VLS modes autovectorization

Simpily extend the current VLA iterator and patterns.

Regression passed with no difference.

gcc/ChangeLog:

	* config/riscv/autovec.md: Add VLS modes.
	* config/riscv/vector.md: Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/vls/def.h: Add VLS FMA/FNMA test.
	* gcc.target/riscv/rvv/autovec/vls/fma-1.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/fma-2.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/fma-3.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/fma-4.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/fnma-1.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/fnma-2.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/fnma-3.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/fnma-4.c: New test.