soc: qcom: dfc: Fix flow control issues

This fixes an use-after-free from dfc_svc_init due to a race
condition in initialization. This also fixes a case where query
is not sent to a particular dfc client.

Change-Id: I2c3d4256e4c7b14a30dd569cb3a451705de12f0e
Acked-by: Ning Cai <ncai@qti.qualcomm.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>