tools: binman: mkimage: add support for passing the engine

mkimage has support for OpenSSL engines but binman currently doesn't for
direct callers of mkimage (e.g. the fit etype). This prepares for adding
support for OpenSSL engines for signing elements of a FIT image, which
will done in the next commit.

Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>

tools/binman/btool/mkimage.py

@@ -22,7 +22,7 @@ class Bintoolmkimage(bintool.Bintool):
 
     # pylint: disable=R0913
     def run(self, reset_timestamp=False, output_fname=None, external=False,
-            pad=None, align=None, keys_dir=None):
+            pad=None, align=None, keys_dir=None, engine=None):
         """Run mkimage
 
         Args:
@@ -35,6 +35,7 @@ class Bintoolmkimage(bintool.Bintool):
                 signatures
             align: Bytes to use for alignment of the FIT and its external data
             keys_dir: Path to directory containing private and encryption keys
+            engine: Name of the OpenSSL engine to use
         """
         args = []
         if external:
@@ -49,6 +50,8 @@ class Bintoolmkimage(bintool.Bintool):
             args += ['-k', f'{keys_dir}']
         if output_fname:
             args += ['-F', output_fname]
+        if engine:
+            args += ['-N', engine]
         return self.run_cmd(*args)
 
     def fetch(self, method):