arm64/sysreg: Generate definitions for CSSELR_EL1

Convert CSSELR_EL1 to automatic generation as per DDI0487H.a, no functional
change.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220520161639.324236-5-broonie@kernel.org


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