Add a REG_P check for inc and dec for Arm MVE

This patch tightens mve_vector_mem_operand to reject non-register operands inside {PRE,POST}_{INC,DEC} addresses by introducing a REG_P check.

This patch fixes this ICE:https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112337

gcc/ChangeLog:

	PR target/112337
	* config/arm/arm.cc (mve_vector_mem_operand): Add a REG_P check for INC
	and DEC operations.

gcc/testsuite/ChangeLog:

	PR target/112337
	* gcc.target/arm/mve/pr112337.c: Test for REG_P check for INC and DEC
	operations.