Makefile: Fix-up new static library to allow linking to work

I made two mistakes in the previous CL:
* All code needs to be compiled with PIC in order to enable linking
* The static library needs to be libmosys.a such that -lmosys will find
  the library.

BUG=chromium:788213
TEST=FEATURES=test USE=static emerge-reef mosys
BRANCH=none

Change-Id: Id8b1cd4fa0e7d40b819468700effac0b5f6d6f69
Reviewed-on: https://chromium-review.googlesource.com/789799
Commit-Ready: Jason Clinton <jclinton@chromium.org>
Tested-by: Jason Clinton <jclinton@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: C Shapiro <shapiroc@google.com>
2 files changed