USB: serial: option: reimplement interface masking

BugLink: http://bugs.launchpad.net/bugs/1774173

commit c3a65808 upstream.

Reimplement interface masking using device flags stored directly in the
device-id table. This will make it easier to add and maintain device-id
entries by using a more compact and readable notation compared to the
current implementation (which manages pairs of masks in separate
blacklist structs).

Two convenience macros are used to flag an interface as either reserved
or as not supporting modem-control requests:

	{ USB_DEVICE(TELIT_VENDOR_ID, TELIT_PRODUCT_ME910_DUAL_MODEM),
	  .driver_info = NCTRL(0) | RSVD(3) },

For now, we limit the highest maskable interface number to seven, which
allows for (up to 16) additional device flags to be added later should
need arise.

Note that this will likely need to be backported to stable in order to
make future device-id backports more manageable.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>