ALSA: emux: improve patch ioctl data validation

stable inclusion
from stable-v4.19.317
commit 40d7def67841343c10f8642a41031fecbb248bab
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEP7
CVE: CVE-2024-42097

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=40d7def67841343c10f8642a41031fecbb248bab



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[ Upstream commit 89b32ccb12ae67e630c6453d778ec30a592a212f ]

In load_data(), make the validation of and skipping over the main info
block match that in load_guspatch().

In load_guspatch(), add checking that the specified patch length matches
the actually supplied data, like load_data() already did.

Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Message-ID: <20240406064830.1029573-8-oswald.buddenhagen@gmx.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>