arm: [MVE intrinsics] add binary_widen_n shape

This patch adds the binary_widen_n shape description.

2022-09-08  Christophe Lyon  <christophe.lyon@arm.com>

	gcc/
	* config/arm/arm-mve-builtins-shapes.cc (binary_widen_n): New.
	* config/arm/arm-mve-builtins-shapes.h (binary_widen_n): New.