Fix stdint.h intptr_t/uintptr_t for x86_64/x32

Patch is required in NDK headers as well to be able to build multilib
GCC with libgomp support.
It's here: https://android-review.googlesource.com/#/c/62982

Change-Id: I2bec25d8cbca0e5ef1a0857008ececd92f4911be
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>