arm64/sysreg: Enable automatic generation of system register definitions

Now that we have a script for generating system registers hook it up to the
build system similarly to cpucaps. Since we don't currently have any actual
register information in the input file this should produce no change in the
built kernel. For ease of review the register information will be converted
in separate patches.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-10-broonie@kernel.org


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