Fix compilation on ARM

Android fix broke ARM compilation on non-Android Linux platforms.
Now correcly define Elf32_auxv_t only on Android/Qt and otherwise
include asm/hwcap.h

Same fix was previously applied to QtScript, which had the exact
same android problem (QTBUG-30978).

Task-number: QTBUG-34917
Change-Id: I29d570731754c6291f8dc0c379e6fdc8ec72b897
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>