ALSA: emu10k1: use dma_set_mask_and_coherent()

We have been calling dma_set_mask() and then dma_set_coherent_mask() with
the same value, but there is a dma_set_mask_and_coherent() function that
does exactly that so let's use it instead.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Takashi Iwai <tiwai@suse.de>