projects: add opensbi project

Add OpenSBI. Pretty standard C project and versioning is as we like it
to be. Did add a commit to interpret *.mk as part of the Makefile
family. Without that, CONFIG_* references aren't found.

https://github.com/riscv-software-src/opensbi
https://riscv.org/wp-content/uploads/2024/12/13.30-RISCV_OpenSBI_Deep_Dive_v5.pdf

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>

elixir/filters/projects.py

@@ -87,6 +87,10 @@ project_filters = {
         # Our solution is to ignore all includes in such paths
         (CppPathIncFilter, {"path_exceptions": {'^/include/uapi/.*'}}),
     ],
+    'opensbi': [
+        *default_filters,
+        *common_kconfig_filters,
+    ],
     'qemu': [
         *default_filters,
         *common_kconfig_filters,

utils/index

@@ -140,6 +140,7 @@ add_default_remotes $1 $# $2 linux https://git.kernel.org/pub/scm/linux/kernel/g
                                    https://github.com/bootlin/linux-history.git
 add_default_remotes $1 $# $2 xen https://xenbits.xen.org/git-http/xen.git
 add_default_remotes $1 $# $2 freebsd https://git.freebsd.org/src.git
+add_default_remotes $1 $# $2 opensbi https://github.com/riscv-software-src/opensbi
 
 # Index a single project
 if test "x$2" != "x--all"; then