ARM: 8529/1: remove 'i' and 'zi' targets

These two targets were introduced by commit 13d5fadf ("[ARM]
Make 'i' and 'zi' targets work") to short-circuit the dependencies
for 'install' and 'zinstall'.

After that, commit 19514fc6 ('arm, kbuild: make "make install"
not depend on vmlinux') eventually made "(z)install" equivalent to
"(z)i".

It is true that 'i' and 'zi' might be still useful as shorthands
but the original intention had been already lost.

They do not even show up in "make ARCH=arm help", so I hope this
deletion does not have much impact.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>