ALSA: line6: Drop invalid SNDRV_PCM_INFO_RESUME flag

The line6 drivers don't support the full resume although they set
SNDRV_PCM_INFO_RESUME.  These flags have to be dropped to inform
properly to the user-space.

Also, drop the CONFIG_PM in trigger callbacks, too, which are rather
superfluous.

Tested-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>