kbuild: set no-integrated-as before incl. arch Makefile

In order to make sure compiler flag detection for ARM works
correctly the no-integrated-as flags need to be set before
including the arch specific Makefile.

Fixes: cfe17c9b ("kbuild: move cc-option and cc-disable-warning after incl. arch Makefile")
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>