Android: fix compile

In early NDKs (previous to 9) Elf32_auxv_t struct was not defined at all.
In NDK 9+ Elf32_auxv_t struct is already defined in elf.h and we'll get an error.
We need to include asm/procinfo.h for HWCAP_VFP.

Change-Id: I1ba30991ea9dd14ad9d7273c58ed6e61cd75255e
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>