Arm32: MSR to SPSR needs qualification

Arm32: MSR to SPSR needs qualification

The Arm ARM's description of MSR (ARM DDI 0406C.d section B9.3.12)
doesn't even allow for plain "SPSR" here, and while gas accepts this, it
takes it to mean SPSR_cf. Yet surely all of SPSR wants updating on this
path, not just the lowest and highest 8 bits.

Fixes: dfcffb128be4 ("xen/arm32: SPSR_hyp/SPSR")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 93031fbe9f4c341a2e7950a088025ea550291433)