gralloc: Fix division-by-0 during system emulation.

This patch avoids a division-by-0 when the system is running
under emulation (the kernel driver reports pixclock as 0, for
some reason). Which results in a SIGFPE during the boot sequence.

Change-Id: Idb6bcdd58999ea9231f2411481c25929d5d02f1d
1 file changed