AndroidKernel.mk: Use Android's prebuilt "make" if available

Switch to using the prebuilt "make" in Android's tree if available.
The Android build system has reduced out-of-tree/host system
module dependency.

Change-Id: I40e8592e162f0b607f96dd31cc8785af3093e485
Signed-off-by: David Ng <dave@codeaurora.org>