kbuild: Fix hostprogs-y

Allow the same target to be specified more than once without causing a warnign from make.
The same target may be specified twice when using the following pattern:
hostprogs-$(CONFIG_FOO) += program
hostprogs-$(CONFIG_BAR) += program
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/Makefile.host

@@ -30,7 +30,7 @@
 # libkconfig.so as the executable conf.
 # Note: Shared libraries consisting of C++ files are not supported
 
-__hostprogs := $(hostprogs-y)$(hostprogs-m)
+__hostprogs := $(sort $(hostprogs-y)$(hostprogs-m))
 
 # hostprogs-y := tools/build may have been specified. Retreive directory
 obj-dirs += $(foreach f,$(__hostprogs), $(if $(dir $(f)),$(dir $(f))))