dt-bindings: nvmem: mediatek: remove duplicate mt8192 line

The same patch was accidentally merged twice, resulting in a
duplicate line for the mt8192 SoC.

Fixes: f2674c0c ("dt-bindings: nvmem: mediatek: add support for MediaTek mt8192 SoC")
Fixes: 2a1405a1 ("dt-bindings: nvmem: mediatek: add support for MediaTek mt8192 SoC")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>