Drop the adv7175 register cache, as it is only written to and never read back
from.  This saves 128 bytes of memory and slightly speeds up the register
writes.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>