lib/charset: fix u16_strlcat() return value

strlcat returns min(strlen(dest), count)+strlen(src). Make u16_strlcat's
behaviour the same for consistency.

Fixes: eca08ce94ceb ("lib/charset: add u16_strlcat() function")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
2 files changed