stm32: use busybox-small, fix hardcoded device nodes and speed

package/busybox-small/Makefile

@@ -43,5 +43,7 @@ do-install:
 	$(CP) $(WRKINST)/* $(IDIR_BUSYBOX_SMALL)/
 	mkdir -p $(IDIR_BUSYBOX_SMALL)/etc
 	$(CP) ./files/inittab $(IDIR_BUSYBOX_SMALL)/etc
+	$(SED) 's#@DEVICE@#$(ADK_RUNTIME_CONSOLE_SERIAL_DEVICE)#g' $(IDIR_BUSYBOX_SMALL)/etc/inittab
+	$(SED) 's#@SPEED@#$(ADK_RUNTIME_CONSOLE_SERIAL_SPEED)#' $(IDIR_BUSYBOX_SMALL)/etc/inittab
 
 include ${ADK_TOPDIR}/mk/pkg-bottom.mk

package/busybox-small/files/inittab

@@ -2,5 +2,5 @@ null::sysinit:/bin/mount -t proc proc /proc
 null::sysinit:/bin/mount -t sysfs sys /sys
 null::sysinit:/bin/mkdir -p /dev/pts
 null::sysinit:/bin/mount -t devpts none /dev/pts
-null::sysinit:/bin/stty -F /dev/ttySC2 38400 cs8 -cstopb -parenb echo
-ttySC2::respawn:/bin/hush -i </dev/ttySC2 >/dev/ttySC2 2>&1
+null::sysinit:/bin/stty -F /dev/@DEVICE@ @SPEED@ cs8 -cstopb -parenb echo
+@DEVICE@::respawn:/bin/hush -i </dev/@DEVICE@ >/dev/@DEVICE@ 2>&1

target/config/Config.in.runtime

@@ -74,6 +74,7 @@ choice
 prompt "base applications"
 depends on !ADK_APPLIANCE_TOOLCHAIN
 default ADK_RUNTIME_BASE_BUSYBOX_SMALL if ADK_TARGET_ARCH_H8300
+default ADK_RUNTIME_BASE_BUSYBOX_SMALL if ADK_TARGET_SYSTEM_ST_STM32F746G
 default ADK_RUNTIME_BASE_NONE if ADK_TARGET_ARCH_C6X
 default ADK_RUNTIME_BASE_BUSYBOX