panfrost: Fix printf format specifier.

bifrost_sampler_descriptor.zero1 is of type uint8_t.

Fix warning reported by Coverity.

Invalid type in argument to printf format specifier (PRINTF_ARGS)
invalid_type: Argument s->zero1 to format specifier %lx was expected to
have type unsigned long but has type unsigned char.

Fixes: 6148d1be ("panfrost: Fix size of bifrost sampler descriptor")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <mesa/mesa!5248>