platform/x86: msi-wmi-platform: Fix typo in WMI GUID

The WMI driver core only supports GUID strings containing only
uppercase characters, however the GUID string used by the
msi-wmi-platform driver contains a single lowercase character.
This prevents the WMI driver core from matching said driver to
its WMI device.

Fix this by turning the lowercase character into a uppercase
character. Also update the WMI driver development guide to warn
about this.

Reported-by: Antheas Kapenekakis <[e-mail]>
Fixes: 9c0beb6b29e7 ("platform/x86: wmi: Add MSI WMI Platform driver")
Tested-by: Antheas Kapenekakis <[e-mail]>
Signed-off-by: Armin Wolf <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Reviewed-by: Ilpo Järvinen <[e-mail]>
Signed-off-by: Ilpo Järvinen <[e-mail]>

Documentation/wmi/driver-development-guide.rst

···
 ::
 
   static const struct wmi_device_id foo_id_table[] = {
+         /* Only use uppercase letters! */
          { "936DA01F-9ABD-4D9D-80C7-02AF85C822A8", NULL },
          { }
   };

drivers/platform/x86/msi-wmi-platform.c

···
 
 #define DRIVER_NAME	"msi-wmi-platform"
 
-#define MSI_PLATFORM_GUID	"ABBC0F6E-8EA1-11d1-00A0-C90629100000"
+#define MSI_PLATFORM_GUID	"ABBC0F6E-8EA1-11D1-00A0-C90629100000"
 
 #define MSI_WMI_PLATFORM_INTERFACE_VERSION	2