arm: testsuite: fix test for armv6t2 hardware

My previous patch series added a new function to check for armv6t2
compatible hardware.  But the test was not correctly implemented and
also did not follow the standard naming convention for Arm hw
compatibility tests.  Fix both of these issues.

gcc/testsuite:

	* lib/target-supports.exp (check_effective_target_arm_arch_v6t2_hw_ok):
	Rename to...
	(check_effective_target_arm_arch_v6t2_hw): ... this.  Fix checks.
	* gcc.target/arm/acle/data-intrinsics-armv6.c: Update pre-check.
	* gcc.target/arm/acle/data-intrinsics-rbit.c: Likewise.