V4L/DVB (8128): saa7146: ->cpu_addr and friends are little-endian

Annotations + stop saa7146_i2c from playing fast and loose with
reuse of ->cpu_addr for host-endian.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>