[media] media: saa7134: remove if based on uninitialized variable

Variable b is not initialized.
Only with a small chance it has random value 0xFF.
Remove if statement based on this value.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>