ref-manual/variables.rst: document the GRUB_MKIMAGE_OPTS variable

This new Grub variable controls the options passed to the grub-mkimage
command in the Grub recipe.

(From yocto-docs rev: 2e5a3c3d5199cad6fb90e0218cdd4a1779743644)

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index dace40f594..20563d61f7 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -3435,6 +3435,11 @@ system and gives an overview of their function and contents.
       See the :ref:`ref-classes-grub-efi` class for more
       information on how this variable is used.
 
+   :term:`GRUB_MKIMAGE_OPTS`
+      This variable controls additional options passed to the ``grub-mkimage``
+      command in the GNU GRand Unified Bootloader (GRUB) recipe during the
+      ``do_mkimage`` task.
+
    :term:`GRUB_OPTS`
       Additional options to add to the GNU GRand Unified Bootloader (GRUB)
       configuration. Use a semi-colon character (``;``) to separate