arm: [MVE intrinsics] add vshlc shape

This patch adds the vshlc shape description.

2024-08-28  Christophe Lyon  <chrirstophe.lyon@linaro.org>

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