libhackrf: Update the library with new fractional sample rate API

And send the new USB command

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
libhackrf: Update the library with new fractional sample rate API

And send the new USB command

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
lib/fw: rename the sample rate function