cris: convert ffs from an object-like macro to a function-like macro

cris: convert ffs from an object-like macro to a function-like macro

This avoids bad interactions with code using identifiers called "ffs":

  drivers/usb/gadget/f_fs.c: In function 'ffsmod_init':
  drivers/usb/gadget/f_fs.c:2693:494: error: 'ffsusb_func' undeclared (first use in this function)
  drivers/usb/gadget/f_fs.c:2693:494: note: each undeclared identifier is reported only once for each function it appears in
  drivers/usb/gadget/f_fs.c: In function 'ffsmod_exit':
  drivers/usb/gadget/f_fs.c:2693:677: error: 'ffsusb_func' undeclared (first use in this function)
  drivers/usb/gadget/f_fs.c: At top level:
  drivers/usb/gadget/f_fs.c:2693:35: warning: 'kernel_ffsusb_func' defined but not used [-Wunused-variable]
  drivers/usb/gadget/f_fs.c: In function 'ffsmod_init':
  drivers/usb/gadget/f_fs.c:2693:15: warning: control reaches end of non-void function [-Wreturn-type]

See http://kisskb.ellerman.id.au/kisskb/buildresult/10715817/

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>