arm64: debug: don't mask DAIF for mdscr_write()

arm64: debug: don't mask DAIF for mdscr_write()

Masking DAIF around the write to MDSCR_EL1 doesn't do anything: we can
write to sysregs with interrupts unmasked, and writing to PSTATE is
not a context synchronization event so it does not synchronize it.

This is done in the context of a general interrupt handling cleanup,
so it does not address the missing context synchronization for the
MDSCR_EL1 write, staying consistent with the current state.  This
should be addressed in a future patch.

Signed-off-by: Ada Couprie Diaz <ada.coupriediaz@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>