Revert "PCI: Add locking to RMW PCI Express Capability Register accessors"

This reverts commit f2d7da8f which is
commit 5e70d0ac upstream.

It breaks the Android API and is not needed for any Android-specific
platforms, so it can be dropped for now.  If it is needed in the future,
it can be brought back in an abi-safe way.

Bug: 161946584
Change-Id: Ic12bc34085f8c7ecea1899f7e14b6ba2a920beba
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>