help: Document CROSS=

should maybe better read "override CROSS_COMPILE from above"

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

Makefile.help

@@ -54,7 +54,8 @@ help:
 	@echo '  V="" 			- Quiet build (default)'
 	@echo '  V=1			- Brief build (show defines, ld flags)'
 	@echo '  V=2			- Very verbose build'
-	@echo '  CROSS_COMPILE=		- Override CROSS_COMPILER_PREFIX from .config'
+	@echo '  CROSS_COMPILE=	- Override CROSS_COMPILER_PREFIX from .config'
+	@echo '  CROSS=		- Same as CROSS_COMPILE'
 	@echo '  ARCH= 		- Use given arch for config targets'
 	@echo '  SHELL=		- Shell to use for make'
 	@echo '  BUILD_CFLAGS=		- extra CFLAGS for compiling host binaries'