Wifi: Move LOCAL_VINTF_FRAGMENTS to executables

Current codebase has the LOCAL_VINTF_FRAGMENTS defined in the static
library definition in Android.mk. This line is skipped and does not take
effect, and hence the Wifi hal service does not start.

Moving the definition to the executable definitions, so it takes effect.

Bug: 141447327
Test: Verify that wifi starts at boot
Change-Id: I9e01483eec4017444689509ea90f761305ae471b