We avoided the explicit use of dma_mmap_coherent() on x86 because of a
spurious warning in x86 APT code in the past.  However, this blindly
assumes that the pages allocated via dma_alloc_coherent() on x86 are
the ones convertible via virt_to_page() (that is used in the default
mmap handler), and it's no longer true; with the indirect DMA ops,
this can be handled differently.  The only certain way for doing mmap
such pages is the dma_mmap_coherent(), and the warning seems already
gone in the recent code, so let's use it consistently.

Link: https://lore.kernel.org/r/20200615160045.2703-2-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>