greybus: camera: Fix endian conversion issues

Convert all Greybus operation fields between CPU and protocol
endianness.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reported-by: Rui Silva <rui.silva@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>