Add Dropbear, missing files.

.gitignore

 .DS_Store
 /output
 /Makefile
+*~

board/raspi/boot/cmdline.txt

+console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 root=/dev/mmcblk0p2 rootwait

board/raspi/boot/config.txt

+kernel=zImage
+
+# To use an external initramfs file
+#initramfs rootfs.cpio.gz
+
+# Disable overscan assuming the display supports displaying the full resolution
+# If the text shown on the screen disappears off the edge, comment this out
+disable_overscan=1
+
+# How much memory in MB to assign to the GPU on Pi models having
+# 256, 512 or 1024 MB total memory
+gpu_mem_256=100
+gpu_mem_512=100
+gpu_mem_1024=100
+
+# 0=NTSC, 2=PAL
+sdtv_mode=0
+
+# 1=4:3, 2=14:9, 3=16:9
+sdtv_aspect=3
+

board/raspi/post_image.sh

+#!/bin/sh
+
+cp $BR2_EXTERNAL/board/raspi/boot/cmdline.txt  $BINARIES_DIR/rpi-firmware/cmdline.txt
+cp $BR2_EXTERNAL/board/raspi/boot/config.txt  $BINARIES_DIR/rpi-firmware/config.txt
+

configs/raspi_defconfig

 BR2_PACKAGE_FFMPEG_SWSCALE=y
 BR2_PACKAGE_RPI_FIRMWARE=y
 # BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTB_OVERLAYS is not set
+BR2_PACKAGE_DROPBEAR=y