staging: line6: Rename capability macros

Including "BIT" in the macro name is pointless.  Replace with "CAP" to
provide some context for what its value represents.

Signed-off-by: Chris Rorvick <chris@rorvick.com>
Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>