ARM: dts: qcom: apq8064-asus-nexus7: add dedicated IMEM compatible

syscon compatible must be preceded with a specific compatible, to
accurately describe the device.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Bjorn Andersson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/arm/boot/dts/qcom-apq8064-asus-nexus7-flo.dts

···
 		};
 
 		sram@2a03f000 {
-			compatible = "syscon", "simple-mfd";
+			compatible = "qcom,apq8064-imem", "syscon", "simple-mfd";
 			reg = <0x2a03f000 0x1000>;
 
 			reboot-mode {