FMCOMMS1: Add a float2fract to handle cal data

Borrowed from something that Michael wrote.

Signed-off-by: Robin Getz <robin.getz@analog.com>
FMCOMMS1: Quiet a few warnings from the last commit I didn't notice

Signed-off-by: Robin Getz <robin.getz@analog.com>
FMCOMMS1: Add Rx phase information to saved cal file.

Signed-off-by: Robin Getz <robin.getz@analog.com>