glibc: Make adjtime() for 32 bit support being called with delta == NULL

This backports a fix from glibc's master branch, which solves a
regression in 2.32 with adjtime() where it would seg fault if being
called with delta == NULL on 32 bit machines.

Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>