device: Add unit to Kconfig option name: `PRE_GRAPHICS_DELAY_MS`

It’s good practice to put the unit into the name.

Change-Id: I1493f61d4e495c22f09abf1829bb2eab9b1fd2b6
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50517
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/device/Kconfig b/src/device/Kconfig
index 421ad66..8dc9ecd 100644
--- a/src/device/Kconfig
+++ b/src/device/Kconfig
@@ -117,7 +117,7 @@
 
 endchoice
 
-config PRE_GRAPHICS_DELAY
+config PRE_GRAPHICS_DELAY_MS
 	int "Graphics initialization delay in ms"
 	default 0
 	depends on VGA_ROM_RUN