Compiler calculates the PciBar[BarIndex] using
sizeof (PciBar[0]) * BarIndex, when BarIndex is type of UINT64,
the above calculation generates assembly code using _allmul.
Change BarIndex to UINTN to avoid the build failure.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>