lnwallet: fix bug in lockTimeToSequence function
lnwallet: fix bug in lockTimeToSequence function

This commit fixes a bug in the lockTimeToSequence function when mapping
a block-based relative lock time to the proper sequence number.

Applying the mask isn’t necessary since the values are expected to be
blow 65K blocks.

aakselrod/lnd,LightningNetwork/lnd,bryanvu/lnd,ddustin/lnd,ddustin/lnd,AndrewSamokhvalov/lnd,AndrewSamokhvalov/lnd,bryanvu/lnd,aakselrod/lnd,LightningNetwork/lnd