Add support for PCMCIA card Sierra WIreless AC850

Add support for Sierra Wireless AC850 which has the same Ids as the
AC710/750 but has a different firmware.

Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>