staging: hikey9xx: update references inside the yaml files

The references inside those files were not assuming that
they would end at the staging tree.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/809bce085b0a9a9ede74d619d160e1e04723709d.1598434228.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/hikey9xx/hisilicon,hi6421-spmi-pmic.yaml

@@ -17,7 +17,7 @@ description: |
   node.
 
   The SPMI controller part is provided by
-  Documentation/devicetree/bindings/spmi/hisilicon,hisi-spmi-controller.yaml.
+  drivers/staging/hikey9xx/hisilicon,hisi-spmi-controller.yaml.
 
 properties:
   $nodename:

drivers/staging/hikey9xx/hisilicon,hisi-spmi-controller.yaml

@@ -14,7 +14,7 @@ description: |
   It is a MIPI System Power Management (SPMI) controller.
 
   The PMIC part is provided by
-  Documentation/devicetree/bindings/mfd/hisilicon,hi6421-spmi-pmic.yaml.
+  drivers/staging/hikey9xx/hisilicon,hi6421-spmi-pmic.yaml.
 
 properties:
   $nodename:
@@ -41,7 +41,7 @@ patternProperties:
       PMIC properties, which are specific to the used SPMI PMIC device(s).
       When used in combination with HiSilicon 6421v600, the properties
       are documented at
-      Documentation/devicetree/bindings/mfd/hisilicon,hi6421-spmi-pmic.yaml.
+      drivers/staging/hikey9xx/hisilicon,hi6421-spmi-pmic.yaml.
 
 examples:
   - |