arm64: zynqmp: Fix comment about number of gpio line names

ZynqMP has 174 gpio lines connected to PS controller but DT is describing
them from 0 to 173 not 174.

Fixes: 7a4c31ee

 ("arm64: zynqmp: Add support for Xilinx Kria SOM board")
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/c3480ba47ac9761903485ebfac127f297053d4da.1634289461.git.michal.simek@xilinx.com


Signed-off-by: Michal Simek <michal.simek@amd.com>