README: Cross-compilation examples

The meminfo example has been corrected to match the Makefile's
"sunxi-meminfo" target, and an example has been added for the
"sunxi-script_extractor" target.
Signed-off-by: Justin Swartz <justin.swartz@risingedge.co.za>
Acked-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

README

@@ -57,15 +57,17 @@ phoenix_info:
 	phoenixcard utility and optionally extracts the embedded boot
 	code & firmware file from their hidden partitions.
 
-meminfo:
+sunxi-meminfo:
 	Tool for reading DRAM settings from registers. Compiled as a
 	static binary for use on android and other OSes. To build this,
 	get a toolchain, and run:
-		make CROSS_COMPILE=arm-linux-gnueabihf- meminfo
+		make CROSS_COMPILE=arm-linux-gnueabihf- sunxi-meminfo
 
-script-extractor:
+sunxi-script_extractor:
 	A simple tool, which can be executed on a rooted Android device
 	to dump the script.bin blob from RAM via reading /dev/mem.
+	To build this, get a toolchain, and run:
+		make CROSS_COMPILE=arm-linux-gnueabihf- sunxi-script_extractor
 
 This software is licensed under the terms of GPLv2+ as defined by the
 Free Software Foundation, details can be read in the COPYING file.