libbladeRF: [WIP] Start of LMS cleanup
libbladeRF: [WIP] < 1/3 through review of LMS code.

Minor aesthetic changes, jotted down a few notes, additional input
validation.
libbladeRF: [WIP] Removed peak detect enable

Per discussion with bpadalino, this was a vestige of some planned
functionality that wasn't completed -- removing for the time being.
libbladeRF: [WIP] Notes, readability, and debug print fix

Prepared a few items (marked XXX) for later discussions and review.
libbladeRF: [WIP] Removed BLADERF_LB_RF_LNA_START

If this is only a placeholder that should never be used, it shouldn't
be presented in external library interface.
libbladeRF: [WIP] Trimmed items from lms_lpf_init, style cleanup
libbladeRF: [WIP] Renamed loopback path configuration function
libbladeRF: [WIP] Fixed swapped parameters
libbladeRF: [WIP] Added debug output in loopback functions
libbladeRF: [WIP] LMS table formatting cleanup
libbladeRF: [WIP] Decoupled enable/disable functions from other configs

Separated out enable/disable functions from other configurations for
consistency and to make the loopback setup a bit easier.

Note that some additional work is still required to bring the device in
and out of loopback modes.
libbladeRF: [WIP] BB_LPF achieved via TXVGA1 output -> RXLPF input

This is just for some preliminary testing. Upcoming commits will
exercise all 9 BB configurations.
libbladeRF: [WIP] Stubbed out new loopback modes