[media] em28xx: remove function em28xx_compression_disable() and its call

em28xx_compression_disable() is a single line function which is called only one
time and this call also isn't needed.
Register 0x26 is always configured as part of the scaler configuration, which
in turn is always done when the resolution changes. And the initial resolution
setting is applied at first device open.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>