CV32E40Pv2 CORE-V SIMD Update

	* gcc/config/riscv/constraints.md: Renamed `const_int2_operand`
	  to `const_int2_simd_operand`.
	* gcc/config/riscv/corev.md: Renamed `const_int2_operand`
	  to `const_int2_simd_operand`.
	* gcc/config/riscv/predicates.md: Changing layout of CORE-V
	  Predicates.
	* gcc/doc/extend.texi: Changing layout of CORE-V Built-in
	  Documentation.