ltq-vmmc: silence missing-prototypes warnings

ltq-vmmc: silence missing-prototypes warnings

There are a lot of missing-prototypes warnings, It's not worth to
fix them one by one.

Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/18744
Signed-off-by: Robert Marko <robimarko@gmail.com>
(cherry picked from commit 144228d61898df387b186a7768df0e4bade868f9)
Signed-off-by: Nora Matthias Schiffer <neocturne@universe-factory.net>
Link: https://github.com/openwrt/openwrt/pull/20440
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>