arm64/mte: Standardise GMID field name definitions

Usually our defines for bitfields in system registers do not include a SYS_
prefix but those for GMID do. In preparation for automatic generation of
defines remove that prefix. No functional change.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220704170302.2609529-9-broonie@kernel.org


Signed-off-by: Will Deacon <will@kernel.org>