ARM: dts: dra7xx: Fix compatible string for PCF8575 chip

The binding definition for the PCF857x GPIO expanders doesn't mention
a "ti,pcf8575" compatible string.  This is apparently because TI is
only a second source - there is no functional difference between
PCF8575 chips manufactured by TI and NXP, and the same board might be
populated with either depending on availability.

This is not a problem in practice because the I2C core uses
of_modalias_node() before matching drivers and this strips the
manufacturer name.
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Acked-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/dra7-evm.dts

@@ -567,7 +567,7 @@ pcf_lcd: gpio@20 {
 	};
 
 	pcf_gpio_21: gpio@21 {
-		compatible = "ti,pcf8575";
+		compatible = "nxp,pcf8575";
 		reg = <0x21>;
 		lines-initial-states = <0x1408>;
 		gpio-controller;

arch/arm/boot/dts/dra72-evm.dts

@@ -422,7 +422,7 @@ tps65917_power_button {
 	};
 
 	pcf_gpio_21: gpio@21 {
-		compatible = "ti,pcf8575";
+		compatible = "nxp,pcf8575";
 		reg = <0x21>;
 		lines-initial-states = <0x1408>;
 		gpio-controller;