[media] msi3101: enhance sampling results

It looks like there is some extra data carried to enhance sampling
results. When you tune to some some weak/empty channel those bits
are always zeroes. When you tune to some channel where is very
strong signals those bits are all zeroes.
Examining those 32-bits reveals shortly there is 16 pieces of 2-bit
numbers. Number seen are 0, 1 and 3 - for some reason 2 is not used.
I used that number to shift bits given amount to left, "increasing"
sampling resolution by 3-bits. It may be wrong, but after some testing
it still provides better signal.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>