bus: mhi: host: Add alignment check for event ring read pointer

mainline inclusion
from mainline-v6.8-rc1
commit eff9704f5332a13b08fbdbe0f84059c9e7051d5f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I99JF1
CVE: CVE-2023-52494

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eff9704f5332a13b08fbdbe0f84059c9e7051d5f



------------------------------------------------------

Though we do check the event ring read pointer by "is_valid_ring_ptr"
to make sure it is in the buffer range, but there is another risk the
pointer may be not aligned.  Since we are expecting event ring elements
are 128 bits(struct mhi_ring_element) aligned, an unaligned read pointer
could lead to multiple issues like DoS or ring buffer memory corruption.

So add a alignment check for event ring read pointer.

Fixes: ec32332d ("bus: mhi: core: Sanity check values from remote device before use")
cc: stable@vger.kernel.org
Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20231031-alignment_check-v2-1-1441db7c5efd@quicinc.com


Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
conflicts:
	drivers/bus/mhi/host/main.c
Signed-off-by: Cai Xinchen <caixinchen1@huawei.com>