scripts: Add Kconfiglib v14.1.0 under scripts directory

We adopt Kconfiglib v14.1.0 sources under scripts directory so that
top-level OpenSBI makefile can directly use Kconfiglib scripts without
expecting users to install a particular version of Kconfiglib on their
build system.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Tested-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>

scripts/Kconfiglib/allyesconfig.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2018-2019, Ulf Magnusson
+# SPDX-License-Identifier: ISC
+
+"""
+Writes a configuration file where as many symbols as possible are set to 'y'.
+
+The default output filename is '.config'. A different filename can be passed
+in the KCONFIG_CONFIG environment variable.
+
+Usage for the Linux kernel:
+
+  $ make [ARCH=<arch>] scriptconfig SCRIPT=Kconfiglib/allyesconfig.py
+"""
+import kconfiglib
+
+
+def main():
+    kconf = kconfiglib.standard_kconfig(__doc__)
+
+    # See allnoconfig.py
+    kconf.warn = False
+
+    # Try to set all symbols to 'y'. Dependencies might truncate the value down
+    # later, but this will at least give the highest possible value.
+    #
+    # Assigning 0/1/2 to non-bool/tristate symbols has no effect (int/hex
+    # symbols still take a string, because they preserve formatting).
+    for sym in kconf.unique_defined_syms:
+        # Set choice symbols to 'm'. This value will be ignored for choices in
+        # 'y' mode (the "normal" mode), which will instead just get their
+        # default selection, but will set all symbols in m-mode choices to 'm',
+        # which is as high as they can go.
+        #
+        # Here's a convoluted example of how you might get an m-mode choice
+        # even during allyesconfig:
+        #
+        #   choice
+        #           tristate "weird choice"
+        #           depends on m
+        sym.set_value(1 if sym.choice else 2)
+
+    # Set all choices to the highest possible mode
+    for choice in kconf.unique_choices:
+        choice.set_value(2)
+
+    kconf.warn = True
+
+    kconf.load_allconfig("allyes.config")
+
+    print(kconf.write_config())
+
+
+if __name__ == "__main__":
+    main()