dt: bindings: add bindings for msa memory region

Add device tree binding documentation details of msa
memory region for ath10k qmi client for SDM845/APQ8098
SoC into "qcom,ath10k.txt".

Signed-off-by: Govind Singh <govinds@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Niklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt

@@ -56,6 +56,11 @@ Optional properties:
 				     the length can vary between hw versions.
 - <supply-name>-supply: handle to the regulator device tree node
 			   optional "supply-name" is "vdd-0.8-cx-mx".
+- memory-region:
+	Usage: optional
+	Value type: <phandle>
+	Definition: reference to the reserved-memory for the msa region
+		    used by the wifi firmware running in Q6.
 
 Example (to supply the calibration data alone):
 
@@ -149,4 +154,5 @@ wifi@18000000 {
 			   <0 140 0 /* CE10 */ >,
 			   <0 141 0 /* CE11 */ >;
 		vdd-0.8-cx-mx-supply = <&pm8998_l5>;
+		memory-region = <&wifi_msa_mem>;
 };