grub-efi: change to generate EFI image in target package

grub-efi: change to generate EFI image in target package

To generate the target EFI image in a native package, it requires
the host gcc have the ability to do -m32/-m64 compiling, but gcc
doesn't have that support on the 32bit version of some distributions
(e.g. rehl, suse), it would fail when build a 64bit target on these
32bit hosts.

In fact, all we need from grub-efi-native is the grub-mkimage binary,
so change the solution to:
 * grub-efi-native only install grub-mkimage
 * grub-efi compiles target modules, generates EFI image
   with grub-mkimage and deploy, but install nothing.

(From OE-Core rev: 53d3f1273983dfce2a907b39768978afe99aab1a)

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>