media: media/platform: fsl-viu.c: fix build for MICROBLAZE

arch/microblaze/ defines out_be32() and in_be32(), so don't do that
again in the driver source.

Fixes these build warnings:

../drivers/media/platform/fsl-viu.c:36: warning: "out_be32" redefined
../arch/microblaze/include/asm/io.h:50: note: this is the location of the previous definition
../drivers/media/platform/fsl-viu.c:37: warning: "in_be32" redefined
../arch/microblaze/include/asm/io.h:53: note: this is the location of the previous definition

Fixes: 29d75068 ("media: fsl-viu: allow building it with COMPILE_TEST")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>