topology: fix potential null pointer from strchr

[GitHub pull_request - opened]

alsa-project/alsa-utils pull request #91 was opened from aiChaoSONG:

This patch adds check to the return pointer from strchr,
because it may be null and cause segment fault, if component
is not properly constructed.

Signed-off-by: Chao Song <chao.song at linux.intel.com>

Request URL   : https://github.com/alsa-project/alsa-utils/pull/91
Patch URL     : https://github.com/alsa-project/alsa-utils/pull/91.patch
Repository URL: https://github.com/alsa-project/alsa-utils