arm64/sysreg: Standardise naming of ID_AA64PFR1_EL1 SME enumeration

In preparation for automatic generation of constants update the define for
SME being implemented to the convention we are using, no functional change.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Kristina Martsenko <kristina.martsenko@arm.com>
Link: https://lore.kernel.org/r/20220905225425.1871461-20-broonie@kernel.org


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>