module: fix signature check failures when using in-kernel decompression

The new flag MODULE_INIT_COMPRESSED_FILE unintentionally trips check in
module_sig_check(). The check was supposed to catch case when version
info or magic was removed from a signed module, making signature
invalid, but it was coded too broadly and was catching this new flag as
well.

Change the check to only test the 2 particular flags affecting signature
validity.

Fixes: b1ae6dc4

 ("module: add in-kernel support for decompressing")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>