RISC-V: Split off shift patterns for autovectorization.

RISC-V: Split off shift patterns for autovectorization.

This patch splits off the shift patterns of the binop patterns.
This is necessary as the scalar shifts require a Pmode operand
as shift count.  To this end, a new iterator any_int_binop_no_shift
is introduced.  At a later point when the binops are split up
further in commutative and non-commutative patterns (which both
do not include the shift patterns) we might not need this anymore.

gcc/ChangeLog:

	* config/riscv/autovec.md (<optab><mode>3): Add scalar shift
	pattern.
	(v<optab><mode>3): Add vector shift pattern.
	* config/riscv/vector-iterators.md: New iterator.