docs/hw/falcon/io: Add missing Falcon register UNK240
This MMIO register was noted in rnndb/falcon.xml, although presently lacks
full documentation.
@@ -147,6 +147,7 @@ Host Falcon Present on Name Description
0x204 0x08100 v4+ units DEBUG_ADDR address for DEBUG_CMD [falcon/debug.txt]
0x208 0x08200 v4+ units DEBUG_DATA_WR debug data to write [falcon/debug.txt]
0x20c 0x08300 v4+ units DEBUG_DATA_RD debug data last read [falcon/debug.txt]
+0x240 0x09000 v5+ units ??? ???
0xfe8 \- GF100- v3 PM_SEL perfmon signal select [falcon/perf.txt]
0xfec \- v0, v3 UC_SP microprocessor $sp reg [falcon/proc.txt]
0xff0 \- v0, v3 UC_PC microprocessor $pc reg [falcon/proc.txt]
