PCI: xilinx-nwl: Fix register misspelling

[ Upstream commit a437027ae1730b8dc379c75fa0dd7d3036917400 ]

MSIC -> MISC

Fixes: c2a7ff18 ("PCI: xilinx-nwl: Expand error logging")
Link: https://lore.kernel.org/r/20240531161337.864994-4-sean.anderson@linux.dev


Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>