MAINTAINERS: update target-mips maintainers

Yongbok Kim takes over the target-mips maintenance from me.
Signed-off-by: NLeon Alrae <leon.alrae@imgtec.com>
Acked-by: NYongbok Kim <yongbok.kim@imgtec.com>
Signed-off-by: NYongbok Kim <yongbok.kim@imgtec.com>

MAINTAINERS

@@ -145,7 +145,7 @@ F: disas/microblaze.c
 
 MIPS
 M: Aurelien Jarno <aurelien@aurel32.net>
-M: Leon Alrae <leon.alrae@imgtec.com>
+M: Yongbok Kim <yongbok.kim@imgtec.com>
 S: Maintained
 F: target-mips/
 F: hw/mips/