Revert "PCI: loongson: Prevent LS7A MRRS increases"

This reverts commit baec889a which is
commit 8b3517f8 upstream.

It breaks the Android kernel abi in the struct pci_host_bridge
structure, and is not needed in any Android devices, so revert it.  If
it is needed in the future it can come back in an abi-safe way.

Bug: 161946584
Change-Id: Ief974ca2a06bc5174efddc03d2938dabee7065d7
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>