ramips: enablemodem: move /lib/ramips.sh to start()

Fix build error: /etc/init.d/enablemodem: line 2: /lib/ramips.sh: No such file or directory

Signed-off-by: Henryk Heisig <hyniu@o2.pl>

target/linux/ramips/base-files/etc/init.d/enablemodem

 #!/bin/sh /etc/rc.common
-. /lib/ramips.sh
 
 START=99
 
 start() {
+	. /lib/ramips.sh
+
 	local board=$(ramips_board_name)
 	if [ $board = "mr200" ]; then
 		adb wait-for-device