[PATCH] Kconfig and Makefile updates, inspired by Adrian Bunk and Roman Zippel

[PATCH] Kconfig and Makefile updates, inspired by Adrian Bunk and Roman Zippel

 - split up saa7146 compilation in core part (saa7146.o) and video+vbi
   part (saa7146_vv).  some drivers need both (av7110.c), some drivers
   only need the core stuff (budget*.c)
 - add entry for sp887x DVB-T modulator to corresponding Kconfig
 - use new SELECT facility of Kconfig, first mentioned by Adrian Bunk
   and Roman Zippel in DVB subsystem
 - use SELECT in media/video/Kconfig, too.