Add vias for reference layer change

[marmeladapk]

• [x] DDS0SYNC{IN,OUT}:

• [x] DDS1_SYNC_IN:

• [x] DDS2_SYNC_IN:

• [x] DDS3_SYNC_IN:

• [x] CK_OSC:

• [x] CK_MMCX

• [x] DDS_CLKA, DDS_CLKB, DDS_CLKB0:

[gkasprow]

I added GND vias where I could fit them