[pattgen] Fix width of literal in pattgen_chan.sv
[pattgen] Fix width of literal in pattgen_chan.sv

I think this was probably copied from the previous line. pda_o should
be a single bit output.

Signed-off-by: Rupert Swarbrick <290093e2ad2515ed2f14d749293c8cf8e02ca274@lowrisc.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan