boot/uboot: bump to version 2015.01

Though U-Boot introduced a Kconfig and Kbuild build system with version
2014.10 the old build commands with <board>_config are still supported.

Tested with BR2_TARGET_UBOOT_BOARDNAME="m28evk"

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/uboot/Config.in

@@ -18,7 +18,7 @@ choice
 	  Select the specific U-Boot version you want to use
 
 config BR2_TARGET_UBOOT_LATEST_VERSION
-	bool "2014.10"
+	bool "2015.01"
 
 config BR2_TARGET_UBOOT_CUSTOM_VERSION
 	bool "Custom version"
@@ -63,7 +63,7 @@ endif
 
 config BR2_TARGET_UBOOT_VERSION
 	string
-	default "2014.10"	if BR2_TARGET_UBOOT_LATEST_VERSION
+	default "2015.01"	if BR2_TARGET_UBOOT_LATEST_VERSION
 	default BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE \
 		if BR2_TARGET_UBOOT_CUSTOM_VERSION
 	default "custom"	if BR2_TARGET_UBOOT_CUSTOM_TARBALL