MAINTAINERS: Drop dt-bindings/genpd/k2g.h

Drop include/dt-bindings/genpd/k2g.h which disappeared from kernel tree
some time back, however MAINTAINERS file was missed to be updated.

Fixes: d1664505 ("dt-bindings: Drop k2g genpd device ID macros")
Cc: Rob Herring <robh@kernel.org>
Cc: Dave Gerlach <d-gerlach@ti.com>
Cc: Santosh Shilimkar <ssantosh@kernel.org>
Cc: Tero Kristo <t-kristo@ti.com>
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>