fix irq flags for iuu_phoenix.c

The file drivers/usb/serial/iuu_phoenix.c uses "int" for flags.  This can
cause hard to find bugs on some architectures.  This patch converts the flags
to use "long" instead.

This bug was discovered by doing an allyesconfig make on the -rt kernel where
checks are done to ensure all flags are of size sizeof(long).

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>