LLRF Digital Board Engineering Changes

AD9765 (U501): Ground GAINCTRL (42), MODE (48), and IQRST (19). Connect IQWRT (17) to IQCLK (18) with a solder bridge.

MAX961 (U3): Ground SHDN (3) and LE (4).

Add 680 pF capacitor from center tap of T1 to ground.

(no picture) Add P2, using carrier board as alignment guide.

(no picture) Short L1.