u-boot: Use mainline u-boot recipe from oe-core

The repository used by u-boot-rpi has not been updated since 2012. In the
meantime, mailine u-boot has gained Raspberry Pi support. All we need to do is
set UBOOT_MACHINE to an appropriate value in the machine config files.

Currently configs are only provided for raspberrypi and raspberrypi2. The master
branch of u-boot now also appears to have a config file for raspberrypi3 so
support for this can be added in the future when u-boot is upgraded in oe-core.

The mainline u-boot recipe creates the file "u-boot.bin" instead of
"u-boot.img".

Signed-off-by: Paul Barker <paul@paulbarker.me.uk>

recipes-bsp/u-boot/u-boot-rpi_git.bb

@@ -1,29 +0,0 @@
-DESCRIPTION = "U-Boot port for RaspberryPi"
-
-require recipes-bsp/u-boot/u-boot.inc
-
-DEPENDS += "rpi-mkimage-native"
-
-PROVIDES += "u-boot"
-
-LICENSE = "GPLv2+"
-LIC_FILES_CHKSUM = "file://COPYING;md5=1707d6db1d42237583f50183a5651ecb"
-
-SRCREV = "6709570cdc947c2a546f96d571551acf4474778c"
-SRC_URI = "git://github.com/gonzoua/u-boot-pi.git;branch=rpi"
-
-S = "${WORKDIR}/git"
-
-UBOOT_MACHINE = "rpi_b"
-UBOOT_MAKE_TARGET = "u-boot.bin"
-UBOOT_SUFFIX = "img"
-
-PACKAGE_ARCH = "${MACHINE_ARCH}"
-
-COMPATIBLE_MACHINE = "raspberrypi"
-
-do_compile_append() {
-    # Create kernel.img from uboot.bin and name it u-boot.img
-    ${STAGING_BINDIR_NATIVE}/imagetool-uncompressed.py u-boot.bin
-    mv kernel.img u-boot.img
-}