Revert "[media] mfd: Add the main bulk of core driver for SI476x code"

This reverts commit b40fe4f6.

Conflicts:
	drivers/mfd/si476x-i2c.c

Requested-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>