drm/bridge: dw-hdmi: Move vmalloc PCM buffer management into the driver

The dw-hdmi drm bridge driver is the only one who still uses the ALSA
vmalloc helper API functions.  A previous attempt to change the way of
buffer management wasn't taken for this legacy stuff, as we had little
chance for test and some risk of major breaking.
Instead, this patch moves the vmalloc buffer stuff into the dw-hdmi
driver code itself, so that we can drop them from ALSA core code
afterwards.

There should be no functional changes.

Link: https://lore.kernel.org/20191210154536.29819-1-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20240807152725.18948-2-tiwai@suse.de