reset: reset-zynqmp: Fixed the argument data type

This patch changes the data type of the variable 'val' from
int to u32.

Addresses-Coverity: argument of type "int *" is incompatible with parameter of type "u32 *"
Signed-off-by: Sai Krishna Potthuri <lakshmi.sai.krishna.potthuri@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/925cebbe4eb73c7d0a536da204748d33c7100d8c.1624448778.git.michal.simek@xilinx.com
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>