Fix definining of ANDROID_SMP.

If TARGET_CPU_SMP is undefined, such as in SDK builds, then the condition as
written before could cause SMP memory barriers to be missing.
Also, add a dependency for Android.mk so that changes to it cause
recompilation.

Change-Id: I63ac0dc4342a39b9355fce2b2200016244cffc4a
1 file changed