AndroidKernel: Explicitly mark certain targets as phony

kerneltags and kernelconfig are phony targets, so mark them
with .PHONY.

Change-Id: I7089d819ff7c64a7b07a0ca5d9de01ec216275b6
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
1 file changed