bootimg_dir is usually set to the value of STAGING_DATADIR and
kernel_dir - to the value of DEPLOY_DIR_IMAGE, so usage of
kernel_dir is more logical in bootimg-efi, bootimg-partition and
rawcopy plugins.
Replaced usage of bootimg_dir to kernel_dir in 3 above mentioned
plugins that use DEPLOY_DIR_IMAGE as a default artifact location.
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
