V4L/DVB (7858): video: build fix for drivers/media/video/mt9v022.c

V4L/DVB (7858): video: build fix for drivers/media/video/mt9v022.c

x86.git testing found the following build bug on latest -git:

  CC [M]  drivers/media/video/mt9v022.o
  drivers/media/video/mt9v022.c: In function 'bus_switch_request':
  drivers/media/video/mt9v022.c:199: error: implicit declaration of function 'gpio_is_valid'
  drivers/media/video/mt9v022.c:201: error: implicit declaration of function 'gpio_request'
  drivers/media/video/mt9v022.c:207: error: implicit declaration of function 'gpio_direction_output'
  drivers/media/video/mt9v022.c:211: error: implicit declaration of function 'gpio_free'
  drivers/media/video/mt9v022.c: In function 'bus_switch_act':
  drivers/media/video/mt9v022.c:237: error: implicit declaration of function 'gpio_set_value_cansleep'
  make[2]: *** [drivers/media/video] Error 2
  make[1]: *** [drivers/media] Error 2
  make[1]: *** Waiting for unfinished jobs....
  make: *** [drivers] Error 2

with this config:

   http://redhat.com/~mingo/misc/config-Sat_May__3_16_08_39_CEST_2008.bad

the bug was that the driver uses GPIO functionality but only includes
the GPIO interface definitions for the CONFIG_MT9M001_PCA9536_SWITCH
case, which was not set in this config.

The quick fix seems to be to include linux/gpio.h unconditionally. (this
seems like a small cleanup as well as it removes and #ifdef is more
robust than an inclusion of asm/gpio.h) Not tested too much yet, so
please have another look in any case.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>