kbuild: factor out the common installation code into scripts/install.sh

Many architectures have similar install.sh scripts.

The first half is really generic; it verifies that the kernel image
and System.map exist, then executes ~/bin/${INSTALLKERNEL} or
/sbin/${INSTALLKERNEL} if available.

The second half is kind of arch-specific; it copies the kernel image
and System.map to the destination, but the code is slightly different.

Factor out the generic part into scripts/install.sh.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>

sparc: Add "install" target

This patches adds an "install" target to install kernel builds for SPARC,
modeled after the i386 script.

Signed-off-by: David L Stevens <david.stevens@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>