MIPS: pci-rt3883: trivial: remove unused variable

Fixes the following compiler warning:
  warning: unused variable 'flags' [-Wunused-variable]

Fixes: e5067c71 ("MIPS: pci-rt3883: Remove odd locking in PCI config space access code")
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: trivial@kernel.org
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>