xen/arm: traps: Remove all zero padding before PRIregister format

xen/arm: traps: Remove all zero padding before PRIregister format

Commit af156ff085 "xen/arm: types: Specify the zero padding in the
definition of PRIregister" moved the zero padding within the definition
of PRIregister.

However, some of the users still had zero padding before which result
to print tens of zero when dumping the CPU state.

To prevent this, remove the last users of zero padding before
PRIregister.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Volodymyr Babchuk <volodymyr.babchuk@epam.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>