mb/system76/gaze16: Rename variant dir

Use the actual model name for the variant dir.

Change-Id: I199b8efb5c3cddb8943ba4b761546caa11c67a30
Signed-off-by: Tim Crawford <tcrawford@system76.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66167
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>

src/mainboard/system76/gaze16/Kconfig

@@ -42,8 +42,8 @@ config MAINBOARD_VERSION
 	default "gaze16-3060-b" if BOARD_SYSTEM76_GAZE16_3060_B
 
 config VARIANT_DIR
-	default "3050" if BOARD_SYSTEM76_GAZE16_3050
-	default "3060" if BOARD_SYSTEM76_GAZE16_3060 || BOARD_SYSTEM76_GAZE16_3060_B
+	default "gaze16-3050" if BOARD_SYSTEM76_GAZE16_3050
+	default "gaze16-3060" if BOARD_SYSTEM76_GAZE16_3060 || BOARD_SYSTEM76_GAZE16_3060_B
 
 config OVERRIDE_DEVICETREE
 	default "variants/\$(CONFIG_VARIANT_DIR)/overridetree.cb"