raspberrypi: bump raspberrypi_dt_defconfig kernel

This brings the raspberrypi_dt_defconfig up to the same kernel used by
the raspberrypi2_defconfig. Also changed the git URL to use HTTP for
consistency.

Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

configs/raspberrypi_dt_defconfig

@@ -11,8 +11,8 @@ BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_3_18=y
 
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_GIT=y
-BR2_LINUX_KERNEL_CUSTOM_REPO_URL="git://github.com/raspberrypi/linux.git"
-BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="246530ff8a4f302b8666c6d9cf509407d8c1257a"
+BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/raspberrypi/linux.git"
+BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="2747cc0bde4ca441691260fae1e34c9ef954ccae"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/raspberrypi/linux-3.18-rpi-dt.defconfig"
 BR2_LINUX_KERNEL_ZIMAGE=y