Revert "net: wwan: mhi_wwan_mbim: Avoid -Wflex-array-member-not-at-end warning"

Revert "net: wwan: mhi_wwan_mbim: Avoid -Wflex-array-member-not-at-end warning"

This reverts commit eeecf5d3a3a484cedfa3f2f87e6d51a7390ed960.

This change lead to MHI WWAN device can't connect to internet.
I found a netwrok issue with kernel 6.19-rc4, but network works
well with kernel 6.18-rc1. After checking, this commit is the
root cause.

Before appliing this serial changes on MHI WWAN network, we shall
revert this change in case of v6.19 being impacted.

Fixes: eeecf5d3a3a4 ("net: wwan: mhi_wwan_mbim: Avoid -Wflex-array-member-not-at-end warning")
Signed-off-by: Slark Xiao <slark_xiao@163.com>
Link: https://patch.msgid.link/20260120072018.29375-1-slark_xiao@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>