3rdparty: Add STM as a submodule

The patch incorporates the STM build as a part of the coreboot
build.  A separate patch lists and documents the options that
the developer can use.  In most cases the default options will
suffice.

Change-Id: I8c6e0c85edd4e2b0658791553bd9947656e8c796
Signed-off-by: Eugene D Myers <cedarhouse@comcast.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44687
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: ron minnich <rminnich@gmail.com>

1 files changed, 0 insertions, 0 deletions

diff --git a/3rdparty/stm b/3rdparty/stm
new file mode 160000
+Subproject 1f3258261a4f4d6c60ec4447c7a03acf2509b98