kbuild: clean up scripts/Makefile.host

The directory creation can be more simplified by two levels.

[1] Drop $(dir ...)

 $(dir $(f)) always returns non-empty string.

So, $(if $(dir $(f)),$(dir $(f)) is equivalent to $(dir $(f)).

[2] Unroll $(foreach ...) loop

$(dir ...) can take one or more arguments and returns a list of
directories of them.

$(foreach f, $(progs), $(dir $(f))) can be unrolled as $(dir $(progs)).
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/Makefile.host

@@ -44,15 +44,11 @@ host-cxxobjs	:= $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs)))
 
 # output directory for programs/.o files
 # hostprogs-y := tools/build may have been specified. Retrieve directory
-host-objdirs := $(foreach f,$(__hostprogs), $(if $(dir $(f)),$(dir $(f))))
+host-objdirs := $(dir $(__hostprogs))
 # directory of .o files from prog-objs notation
-host-objdirs += $(foreach f,$(host-cmulti),                  \
-                    $(foreach m,$($(f)-objs),                \
-                        $(if $(dir $(m)),$(dir $(m)))))
+host-objdirs += $(dir $(foreach f,$(host-cmulti), $($(f)-objs)))
 # directory of .o files from prog-cxxobjs notation
-host-objdirs += $(foreach f,$(host-cxxmulti),                  \
-                    $(foreach m,$($(f)-cxxobjs),                \
-                        $(if $(dir $(m)),$(dir $(m)))))
+host-objdirs += $(dir $(foreach f,$(host-cxxmulti), $($(f)-cxxobjs)))
 
 host-objdirs := $(strip $(sort $(filter-out ./,$(host-objdirs))))