[media] media: mx2_camera: Change Kconfig dependency

This patch change MACH_MX27 dependency to SOC_IMX27 for MX2 camera
driver, since MACH_MX27 symbol is scheduled for removal.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>