ALSA: timer: check if timer->card is null before using it

NULL check timer->card before use to prevent dereferencing
a NULL pointer.

CRs-Fixed: 1046606
Change-Id: I8e359864508cc2307d9e9619f36c7c08cc3842f9
Signed-off-by: Meng Wang <mwang@codeaurora.org>
1 file changed