ANDROID: GKI: add ww_mutex_trylock to db845c symbol list

In commit 20406ace ("drm/msm: use trylock for debugfs"), the msm
driver took a new symbol dependency, ww_mutex_trylock, so add it to the
db845c symbol list to fix the build.

Fixes: 20406ace ("drm/msm: use trylock for debugfs")
Change-Id: I955baa8240e06dac15578204e917812f563d73b8
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>