nitrogen6x_defconfig: drop double linux tarball location

Somehow the old setting wasn't dropped in 184850a42 (bump u-boot /
linux versions to current stable).

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

configs/nitrogen6x_defconfig

@@ -19,7 +19,6 @@ BR2_TARGET_UBOOT_CUSTOM_TARBALL_LOCATION="http://github.com/boundarydevices/u-bo
 # kernel
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_TARBALL=y
-BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="http://github.com/boundarydevices/linux-imx6/tarball/5f84e92/linux-imx6-5f84e92.tar.gz"
 BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="http://github.com/boundarydevices/linux-imx6/tarball/2dc5560/linux-imx6-2dc5560.tar.gz"
 BR2_LINUX_KERNEL_DEFCONFIG="nitrogen6x"
 BR2_LINUX_KERNEL_INSTALL_TARGET=y