buildman: README: add links for toolchains not available on kernel.org

Add links for toolchains not available on kernel.org.

The sh4 toolchains from kernel.org dose not work for some boards,
so use the sh from Sourcery.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/buildman/README

@@ -156,7 +156,6 @@ aarch64: /opt/linaro/gcc-linaro-aarch64-none-elf-4.8-2013.10_linux
 [toolchain-alias]
 x86: i386
 blackfin: bfin
-sh: sh4
 nds32: nds32le
 openrisc: or32
 
@@ -341,6 +340,28 @@ Testing
          - found '/home/sjg/.buildman-toolchains/gcc-4.5.1-nolibc/or32-linux/bin/or32-linux-gcc'
 Tool chain test:  OK
 
+Or download them all from kernel.org and move them to /toolchains directory,
+
+$ for i in aarch64 arm avr32 i386 m68k microblaze mips or32 powerpc sparc
+  do
+  ./tools/buildman/buildman --fetch-arch $i
+  done
+$ sudo mkdir -p /toolchains
+$ sudo mv ~/.buildman-toolchains/*/* /toolchains/
+
+For those not available from kernel.org, download from the following links.
+
+arc: https://github.com/foss-for-synopsys-dwc-arc-processors/toolchain/releases/
+    arc_gnu_2015.06_prebuilt_uclibc_le_archs_linux_install.tar.gz
+blackfin: http://sourceforge.net/projects/adi-toolchain/files/
+    blackfin-toolchain-elf-gcc-4.5-2014R1_45-RC2.x86_64.tar.bz2
+nds32: http://osdk.andestech.com/packages/
+    nds32le-linux-glibc-v1.tgz
+nios2: http://sourcery.mentor.com/public/gnu_toolchain/nios2-linux-gnu/
+    sourceryg++-2015.11-27-nios2-linux-gnu-i686-pc-linux-gnu.tar.bz2
+sh: http://sourcery.mentor.com/public/gnu_toolchain/sh-linux-gnu/
+    renesas-4.4-200-sh-linux-gnu-i686-pc-linux-gnu.tar.bz2
+
 Buildman should now be set up to use your new toolchain.
 
 At the time of writing, U-Boot has these architectures: