[media] davinci: vpif: remove machine specific header file includes

remove unnecessary inclusion of machine specific header files mach/dm646x.h,
mach/hardware.h from vpif.h  and aslo mach/dm646x.h from vpif_display.c
driver which comes in the way of platform code consolidation.
Add linux/i2c.h header file in vpif_types.h which is required for
building.

Signed-off-by: Manjunath Hadli <manjunath.hadli@ti.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: LMML <linux-media@vger.kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>