fix sideload to use update.img filename and install_rkimage() call
adb sideload only used package.zip and install_package() for google images.
changed it to use update.img and install_rkimage() call for rockchip fw images
adb sideload only used package.zip and install_package() for google images.
changed it to use update.img and install_rkimage() call for rockchip fw images