pci: pcie_dw_rockchip: Drop the unused variable warning

pci: pcie_dw_rockchip: Drop the unused variable warning

Drop the unused variable warning below.

drivers/pci/pcie_dw_rockchip.c:161:6: warning: unused variable
'val' [-Wunused-variable]
  161 |  u32 val;
       |      ^~~
Cc: Patrick Wildt <patrick@blueri.se>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Patrick Wildt <patrick@blueri.se>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>