Fix the apt package install abort because of missing -y (sonic-net#40)

Author: tirupatihemanth

build_debian.sh

@@ -447,7 +447,7 @@ if [[ $TARGET_BOOTLOADER == grub ]]; then
         GRUB_PKG=grub-efi-arm64-bin
     fi
 
-    sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get install -d -o dir::cache=/var/cache/apt \
+    sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y install -d -o dir::cache=/var/cache/apt \
         $GRUB_PKG
 
     sudo cp $FILESYSTEM_ROOT/var/cache/apt/archives/grub*.deb $FILESYSTEM_ROOT/$PLATFORM_DIR/grub