MAINTAINERS: Remove reference to shmobile / koelsch_defconfig

koelsch_defconfig has been removed.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

MAINTAINERS

@@ -1381,7 +1381,6 @@ F:	arch/arm/boot/dts/sh*
 F:	arch/arm/configs/ape6evm_defconfig
 F:	arch/arm/configs/armadillo800eva_defconfig
 F:	arch/arm/configs/bockw_defconfig
-F:	arch/arm/configs/koelsch_defconfig
 F:	arch/arm/configs/kzm9g_defconfig
 F:	arch/arm/configs/lager_defconfig
 F:	arch/arm/configs/mackerel_defconfig