RISC-V: Support VLS INT <-> FP conversions

RISC-V: Support VLS INT <-> FP conversions

Support INT <-> FP VLS auto-vectorization patterns.

Regression passed.
Committed.

gcc/ChangeLog:

	* config/riscv/autovec.md: Extend VLS modes.
	* config/riscv/vector-iterators.md: Ditto.
	* config/riscv/vector.md: Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/vls/convert-1.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-10.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-11.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-12.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-2.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-3.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-4.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-5.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-6.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-7.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-8.c: New test.
	* gcc.target/riscv/rvv/autovec/vls/convert-9.c: New test.