This is a slightly intensive rewrite of Kconfig and Makefile about
ALSA sequencer stuff.
The first major change is that the kconfig items for the sequencer are
moved to sound/core/seq/Kconfig. OK, that's easy.
The substantial change is that, instead of hackish top-level module
selection in Makefile, we define a Kconfig item for each sequencer
module. The driver that requires such sequencer components select
exclusively the kconfig items. This is more straightforward and
standard way.
Signed-off-by: Takashi Iwai <tiwai@suse.de>