dt-bindings: serial: 8250: Remove duplicated compatible strings

stable inclusion
from stable-5.10.38
commit 81cb4f36d62c37ee0c81c57718b4afe12e2bece6
bugzilla: 51875
CVE: NA

--------------------------------

commit a7277a73 upstream.

The compatible strings "mediatek,*" appears two times, remove one of them.

Fixes: e69f5dc6 ("dt-bindings: serial: Convert 8250 to json-schema")
Signed-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210422090857.583-1-thunder.leizhen@huawei.comSigned-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

Documentation/devicetree/bindings/serial/8250.yaml

@@ -93,11 +93,6 @@ properties:
               - mediatek,mt7622-btif
               - mediatek,mt7623-btif
           - const: mediatek,mtk-btif
-      - items:
-          - enum:
-              - mediatek,mt7622-btif
-              - mediatek,mt7623-btif
-          - const: mediatek,mtk-btif
       - items:
           - const: mrvl,mmp-uart
           - const: intel,xscale-uart