efi_loader: check the status of disconnected drivers

efi_uninstall_protocol() calls efi_disconnect_all_drivers() but never
checks the return value.  Instead it tries to identify protocols that
are still open after closing the ones that were opened with
EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL, EFI_OPEN_PROTOCOL_GET_PROTOCOL
and EFI_OPEN_PROTOCOL_TEST_PROTOCOL.

Instead of doing that,  check the return value early and exit if
disconnecting the drivers failed.  Also reconnect all the drivers of
a handle if protocols are still found on the handle after disconnecting
controllers and closing the remaining protocols.

While at it fix a memory leak and properly free the opened protocol
information when closing a protocol.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>