drm/xe/xe2: fix 64-bit division in pte_update_size

drm/xe/xe2: fix 64-bit division in pte_update_size

This function does not build on 32-bit targets when the compiler
fails to reduce DIV_ROUND_UP() into a shift:

ld.lld: error: undefined symbol: __aeabi_uldivmod
>>> referenced by xe_migrate.c
>>>               drivers/gpu/drm/xe/xe_migrate.o:(pte_update_size) in archive vmlinux.a

There are two instances in this function. Change the first to
use an open-coded shift with the same behavior, and the second
one to a 32-bit calculation, which is sufficient here as the size
is never more than 2^32 pages (16TB).

Fixes: 237412e45390 ("drm/xe: Enable 32bits build")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240226124736.1272949-3-arnd@kernel.org
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>