sparc,sparc64: unify Makefile

To unify Makefile for sparc and sparc64 a few other steps was needed:
1) separate defconfig files for sparc and sparc64 is required,
   so locate these in arch/sparc/configs
2) removoval of hack in toplevel Makefile to deal with that
   headers was in a separate directory compared to the rest

The unification of the Makefile required usage of several

    foo-$(CONFIG_SPARCnn) +=

due to a few directories pending unification.
This will be cleaned up when we unify the remaining directories.

Included in this patch are the deletion of a few files in
sparc64 as they are no longer needed: Makefile + Kconfig.
arch/sparc64/ will after this patch is applied only
have four directories (prom, lib, kernel, boot)

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Makefile b/Makefile
index 9a49960..7ec3b97 100644
--- a/Makefile
+++ b/Makefile
@@ -205,13 +205,14 @@
         SRCARCH := x86
 endif
 
-# Where to locate arch specific headers
+# Additional ARCH settings for sparc
 ifeq ($(ARCH),sparc64)
-       hdr-arch  := sparc
-else
-       hdr-arch  := $(SRCARCH)
+       SRCARCH := sparc
 endif
 
+# Where to locate arch specific headers
+hdr-arch  := $(SRCARCH)
+
 KCONFIG_CONFIG	?= .config
 
 # SHELL used by kbuild