Removing the dependency on vmlinux for the install target raised a few
complaints, so instead a new target i added: kernel_install.

kernel_install will install the kernel just like the ordinary install target.
The only difference is that install has a dependency on vmlinux,
kernel_install does not. Therefore kernel_install is the best choice
when accessing the kernel over a NFS mount or as another user.

kernel_install is similar to modules_install in the fact that neither does
a full kernel compile before performing the install.
In this way they are good for root use. Also added back the
dependency on vmlinux for the install target so peoples scripts are no
longer broken.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>