Latest busybox version cannot be used

busybox sha1 76915bf7 (2015-12-19) makes use of MTD_FILE_MODE_RAW.
This is correctly defined in linux/include/uapi/mtd/mtd-abi.h, but
unfortunately not in the toolchain headers
<toolchain>/arm-linux-gnueabihf/libc/usr/include/mtd/mtd-abi.h

Hence the previous sha1 is to be used, that is dbf5a6da

Change-Id: Iec81120623161349cbe2c35601b112d4235f60dc
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
Tested-by: Pascal Brand <pascal.brand@linaro.org> (QEMU)
Signed-off-by: Pascal Brand <pascal.brand@st.com>
diff --git a/fvp.xml b/fvp.xml
index 47df8dc..6181462 100644
--- a/fvp.xml
+++ b/fvp.xml
@@ -15,7 +15,7 @@
 	<project path="optee_test" name="optee_test.git" />
 
 	<!-- busybox -->
-	<project remote="busybox" path="busybox" name="busybox.git" />
+	<project remote="busybox" path="busybox" name="busybox.git" revision="dbf5a6da6a4295ce26edd1ce34fde567d19afa02" />
 
 	<!-- ARM gits, FVP -->
 	<!-- <project remote="arm" path="arm-trusted-firmware" name="arm-trusted-firmware.git" /> -->