[ALSA] emu10k1: There's no need to cast vmalloc() return value in snd_emu10k1_create()

vmalloc() returns void *. no need to cast.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>