Ensure proper default value for LpGBT EQAttenuation

From the commit message:

For the longest time, the EQConfig[0x037] register was set to 0x18. This goes against the recommendations from the LpGBT manual which mandates using a value of '1/1' (i.e. 2'd3) for the EQAttenuation[bits 1:0] parameter instead of '2/3' (i.e. '2'd2') when a VTRx+ is used. This is specified in both the Quick Start guide and the register map.

It was noticed during configuration testing that the transaction writing the EQConfig[0x037] was often failing on one of the ASIAGO. The issue is resolved when using the recommended value.

Additional information can be found in the LpGBT manual:

• Quick Start guide: https://lpgbt.web.cern.ch/lpgbt/v1/quickStart.html#downlink-equalizer-if-high-speed-receiver-is-used
• Register map: https://lpgbt.web.cern.ch/lpgbt/v1/registermap.html#x037-eqconfig