s390: drop redundant directory creation from tools Makefile

As you can see in scripts/Kbuild.include, the filechk creates the
parent directory of the target as needed.

This Makefile does not need to explicitly create the directory.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

arch/s390/tools/Makefile

@@ -16,9 +16,6 @@ hostprogs-y		    += gen_opcode_table
 
 HOSTCFLAGS_gen_facilities.o += $(LINUXINCLUDE)
 
-# Ensure output directory exists
-_dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
-
 filechk_facility-defs.h = $(obj)/gen_facilities
 
 filechk_dis-defs.h = \