kbuild: drop descend - converting existing users

There was only two users left of descend. Fix them so they
use $(clean)= and $(build)=.
Drop definition of descend.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
---
diff --git a/Makefile b/Makefile
index 7719874..7e4624a 100644
--- a/Makefile
+++ b/Makefile
@@ -1356,11 +1356,6 @@
 # $(Q)$(MAKE) $(clean)=dir
 clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj
 
-#	$(call descend,<dir>,<target>)
-#	Recursively call a sub-make in <dir> with target <target>
-# Usage is deprecated, because make does not see this as an invocation of make.
-descend =$(Q)$(MAKE) -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj=$(1) $(2)
-
 endif	# skip-makefile
 
 FORCE:
diff --git a/arch/m68knommu/Makefile b/arch/m68knommu/Makefile
index a254aa9..58c9fa5 100644
--- a/arch/m68knommu/Makefile
+++ b/arch/m68knommu/Makefile
@@ -109,7 +109,7 @@
 prepare: include/asm-$(ARCH)/asm-offsets.h
 
 archclean:
-	$(call descend arch/$(ARCH)/boot, subdirclean)
+	$(Q)$(MAKE) $(clean)=arch/m68knommu/boot
 
 include/asm-$(ARCH)/asm-offsets.h: arch/$(ARCH)/kernel/asm-offsets.s \
 				   include/asm include/linux/version.h \
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index bc1c442..26528b6 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -683,7 +683,7 @@
 
 ifdef CONFIG_LASAT
 rom.bin rom.sw: vmlinux
-	$(call descend,arch/mips/lasat/image,$@)
+	$(Q)$(MAKE) $(build)=arch/mips/lasat/image $@
 endif
 
 #
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 7cf75cc..6e079f3 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -229,11 +229,6 @@
 
 cmd = @$(if $($(quiet)cmd_$(1)),echo '  $(subst ','\'',$($(quiet)cmd_$(1)))' &&) $(cmd_$(1))
 
-#	$(call descend,<dir>,<target>)
-#	Recursively call a sub-make in <dir> with target <target> 
-# Usage is deprecated, because make do not see this as an invocation of make.
-descend =$(Q)$(MAKE) -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj=$(1) $(2)
-
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 # Usage:
 # $(Q)$(MAKE) $(build)=dir