[klibc] Kbuild: Remove KLIBCKERNELOBJ variable

Since the UAPI/KAPI header split in Linux 3.7, we have needed
KLIBCKERNELSRC to point to the installed UAPI headers.  This makes
KLIBCKERNELOBJ and the extra header directories based on it completely
redundant.

Link: https://www.zytor.com/pipermail/klibc/2019-January/004031.html
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
7 files changed