[media] xc4000: cut over to using xc5000 version for loading i2c sequences

The xc3028 version does i2c splitting in a different manner than xc4000 and
xc5000, so reuse the xc5000 version of the routine (the key here being that
xc4000 expects the first *two* bytes to be the same for splitting transactions.

Doing it the xc3028 way was resulting in i2c errors partially through the
firmware load.  With this change, it would appear that the entire base firmware
is being loaded successfully (product id now properly shows 0x0FA0).

Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>