msm: vidc: fix error during debugfs init

When CONFIG_DEBUG_FS is disabled, the call to
debugfs_create_dir will result in an error.

Add a check of the config to avoid the error.

Change-Id: I7a79dbc5c4c5e1e3192a11d55ad9b7994788f30f
Signed-off-by: ziqic <quic_ziqic_01@quicinc.com>