dt-bindings: remoteproc: qcom: Add firmware bindings for Q6V5

Add optional "firmware-name" bindings for Q6V5 MSS and PAS based
remoteprocs. For Q6V5 MSS/PAS the two/one relative firmware
paths/path are to be listed respectively. Fallback to the default
images for mba/modem for Q6V5 MSS or the default Hexagon image
for Q6V5 PAS if the "firmware-name" binding is not present.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Documentation/devicetree/bindings/remoteproc/qcom,adsp.txt

@@ -27,6 +27,12 @@ on the Qualcomm ADSP Hexagon core.
 	Value type: <stringlist>
 	Definition: must be "wdog", "fatal", "ready", "handover", "stop-ack"
 
+- firmware-name:
+	Usage: optional
+	Value type: <string>
+	Definition: must list the relative firmware image path for the
+		    Hexagon Core.
+
 - clocks:
 	Usage: required
 	Value type: <prop-encoded-array>

Documentation/devicetree/bindings/remoteproc/qcom,q6v5.txt

@@ -36,6 +36,13 @@ on the Qualcomm Hexagon core.
 	Value type: <stringlist>
 	Definition: must be "wdog", "fatal", "ready", "handover", "stop-ack"
 
+- firmware-name:
+	Usage: optional
+	Value type: <stringlist>
+	Definition: must list the relative firmware image paths for mba and
+		    modem. They are used for booting and authenticating the
+		    Hexagon core.
+
 - clocks:
 	Usage: required
 	Value type: <phandle>