Fix for BUG 473:  UHD: DBSRX2 VCO Autoselect Failing / Wrong Frequency Range
- Corrected frequency range for DBSRX2
- Corrected register write order when changing frequency
Fix for BUG 456:  LED TX/RX colors backwards on X300
- Corrected bit masks so TX will light the red LED and RX will light the green LED
Fixed whitespace and added comment.
x300: Fixing Bug 456 - backwards LED colors.
Fixing Bug #473 - Autoselection of VCO Frequency in DBSRX2
x300: adding include to fix builds on older systems