target/linux/*/base-files/lib/upgrade/platform.sh - wrong check for ARGC

ARGC is a 'C-ism', but not known/valid in shell-syntax - insert the correct
var $# (=number of args) here. under normal conditions this had no impact,
but we should at least correct it. the error was observable like this:

root@box:~ [ -e "/etc/functions.sh" ] && . /etc/functions.sh
root@box:~ [ -e "/lib/functions.sh" ] && . /lib/functions.sh
root@box:~ . /lib/upgrade/platform.sh
root@box:~ . /lib/upgrade/common.sh
root@box:~ platform_check_image /tmp/myfirmware.bin
ash: bad number
root@box:~ echo $?
0

Signed-off-by: Bastian Bittorf <bittorf@bluebottle.com>

SVN-Revision: 40915

target/linux/adm5120/base-files/lib/upgrade/platform.sh

@@ -10,7 +10,7 @@ RAMFS_COPY_DATA=/lib/adm5120.sh
 platform_check_image() {
 	local magic="$(get_magic_word "$1")"
 
-	[ "$ARGC" -gt 1 ] && return 1
+	[ "$#" -gt 1 ] && return 1
 
 	case "$board_name" in
 	"ZyXEL"*|"Compex WP54 family")