cpu/x86: add pae paging module to all stages

cpu/x86: add pae paging module to all stages

In preparation for bringing in paging early always provide the
paging pae module to all stages. Since we cull unused symbols this
is a no-op. Compilation testing will happen all the time since the module
currently doesn't compile without <arch/cpu.h> include.  The current
file is completely guarded with ENV_RAMSTAGE because it's using
cpu_index() which is a ramstage-only construct.

BUG=b:72728953

Change-Id: Ib4310b8206e5247fa220b42203bcd18d522d51ea
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/25712
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Justin TerAvest <teravest@chromium.org>