Clean up of X86 build flags

Review and clean-up of both compiler and linker flags
to ensure proper usage and consistency for images, toolchain,
SDK, and NDK.

Change-Id: Ife75c32cd49b32345712dee28fa5f2283069a90e
Signed-off-by: Mark D Horn <mark.d.horn@intel.com>
Author: Bruce Beare <bruce.j.beare@intel.com>