[PATCH] doc: board/qualcomm: remove signing references from dragonwing.rst

[Casey Connolly]

The mkmbn tool isn't available yet, so it's still necessary to use
qtestsign for signing.

Update the docs to describe it, this can be reverted once mkmbn and the
associated tooling is merged.

Signed-off-by: Casey Connolly <casey.connolly at linaro.org>
---
 doc/board/qualcomm/dragonwing.rst | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/doc/board/qualcomm/dragonwing.rst b/doc/board/qualcomm/dragonwing.rst
index 12a0bfb3544b..d48994153095 100644
--- a/doc/board/qualcomm/dragonwing.rst
+++ b/doc/board/qualcomm/dragonwing.rst
@@ -21,13 +21,16 @@ First, setup ``CROSS_COMPILE`` for aarch64. Then, build U-Boot for ``QCS615``, `
   $ export CROSS_COMPILE=<aarch64 toolchain prefix>
   $ make qcom_qcs8300_defconfig
   $ make -j8 u-boot.mbn
 
-This will build the signed ``u-boot.mbn`` in the configured output directory.
-The firmware expects firmware ELF images to be "signed". The signature
-does not provide any security in this case, but it provides the firmware
-with some required metadata. More information
-about image signing can be found in :doc:`signing`.
+Although the board does not have secure boot set up by default,
+the firmware still expects firmware ELF images to be "signed". The signature
+does not provide any security in this case, but it provides the firmware with
+some required metadata.
+
+To "sign" ``u-boot.elf`` you can use e.g. `qtestsign`_::
+
+  $ qtestsign -v6 aboot -o u-boot.mbn u-boot.elf
 
 Then flash the resulting ``u-boot.mbn`` to the ``uefi_a`` partition
 on your device with ``fastboot flash uefi_a u-boot.mbn``.
 
-- 
2.49.0