ArmPkg/PlatformBootManagerLib: process pending capsules

ArmPkg/PlatformBootManagerLib: process pending capsules

Process any capsule HOBs that were left for us by CapsulePei. This
involves calling ProcessCapsules() twice, as explained in the comment
in DxeCapsuleLibFmp [sic].

1) The first call must be before EndOfDxe. The system capsules is processed.
   If device capsule FMP protocols are exposted at this time and device FMP
   capsule has zero EmbeddedDriverCount, the device capsules are processed.
   Each individual capsule result is recorded in capsule record variable.
   System may reset in this function, if reset is required by capsule and
   all capsules are processed.
   If not all capsules are processed, reset will be defered to second call.

2) The second call must be after EndOfDxe and after ConnectAll, so that all
   device capsule FMP protocols are exposed.
   The system capsules are skipped. If the device capsules are NOT processed
   in first call, they are processed here.
   Each individual capsule result is recorded in capsule record variable.
   System may reset in this function, if reset is required by capsule
   processed in first call and second call.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>