MdeModulePkg/PciBus: Fix bug that doesn't produce BusOverride

MdeModulePkg/PciBus: Fix bug that doesn't produce BusOverride

It's a regression of below commit:
SHA-1: 8be37a5cee700777ca8e8e8a34cc2225b21931a7
* MdeModulePkg/SecurityStubDxe: Defer 3rd party image before EndOfDxe

When PciBus driver fails to load the Option ROM, it doesn't produce
BusOverride protocol. It was a correct behavior before the above
commit. But due to the above commit, BusOverride protocol never is
produced by PciBus driver.

The patch fixes this issue using the following solution:
1. PciBus records the image device path when LoadImage fails.
2. Override.GetDriver() tries to look for the image handle using
   the stored image device path.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>