ALSA: oss: consolidate kmalloc/memset 0 call to kzalloc

commit 46325371b230cc66c743925c930a17e7d0b8211e upstream.

This is an API consolidation only. The use of kmalloc + memset to 0
is equivalent to kzalloc.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>