[media] shark,shark2: declare resume/suspend functions as static

drivers/media/radio/shark2.o: In function `_GLOBAL__sub_I_65535_0_usb_shark_suspend':
drivers/media/radio/radio-shark2.c:344: multiple definition of `usb_shark_suspend'
drivers/media/radio/radio-shark.o:/home/v4l/v4l/patchwork/drivers/media/radio/radio-shark.c:379: first defined here
drivers/media/radio/shark2.o: In function `usb_shark_resume':
drivers/media/radio/radio-shark2.c:349: multiple definition of `usb_shark_resume'
drivers/media/radio/radio-shark.o:/home/v4l/v4l/patchwork/drivers/media/radio/radio-shark.c:384: first defined here

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>