ALSA: docs: fix typo

GFP_KRENEL -> GFP_KERNEL

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

Link: https://lore.kernel.org/r/1596224129-7699-1-git-send-email-Julia.Lawall@inria.fr


Signed-off-by: Takashi Iwai <tiwai@suse.de>