ALSA: pcm - fix mmap capability check for the snd-dummy driver

stable inclusion
from stable-5.10.58
commit c0b626f0a29a966d37d6dd7784005e47b38c1497
bugzilla: 176984 https://gitee.com/openeuler/kernel/issues/I4E2P4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c0b626f0a29a966d37d6dd7784005e47b38c1497



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commit 852a8a97 upstream.

The snd-dummy driver (fake_buffer configuration) uses the ops->page
callback for the mmap operations. Allow mmap for this case, too.

Cc: <stable@vger.kernel.org>
Fixes: c4824ae7 ("ALSA: pcm: Fix mmap capability check")
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210730090254.612478-1-perex@perex.cz


Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>