ARM: at91/dt: fix macb pinctrl_macb_rmii_mii_alt definition

The PA24 pin is wrongly assigned to peripheral B.
In the current config there is 2 ETX3 pins (PA11 and PA24) and
no ETXER pin (PA22).
Signed-off-by: NBoris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable <stable@vger.kernel.org> # 3.8+

arch/arm/boot/dts/at91sam9260.dtsi

@@ -264,7 +264,7 @@
 						atmel,pins =
 							<0 10 0x2 0x0	/* PA10 periph B */
 							 0 11 0x2 0x0	/* PA11 periph B */
-							 0 24 0x2 0x0	/* PA24 periph B */
+							 0 22 0x2 0x0	/* PA22 periph B */
 							 0 25 0x2 0x0	/* PA25 periph B */
 							 0 26 0x2 0x0	/* PA26 periph B */
 							 0 27 0x2 0x0	/* PA27 periph B */