OSS is deprecated yet currently it is reported to be more stable
therefore we keep it but make it optional
Revert the conditional compilation:
	add  CONFIG_EASYCAP_OSS and kill EASYCAP_NEEDS_ALSA
move oss-only code from easycap_sound.c to easycap_sound_oss.c

Cc: Mike Thomas <rmthomas@sciolus.org>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>