x86/build: Make 64-bit defconfig the default

Running 'make ARCH=x86 defconfig' on anything other than an x86_64
machine currently results in a 32-bit build, which is rarely what
anyone wants these days.

Change the default so that the 64-bit config gets used unless
the user asks for i386_defconfig, uses ARCH=i386 or runs on
a system that "uname -m" identifies as i386/i486/i586/i686.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230215091706.1623070-1-arnd@kernel.org

arch/x86/Makefile

@@ -3,10 +3,10 @@
 
 # select defconfig based on actual architecture
 ifeq ($(ARCH),x86)
-  ifeq ($(shell uname -m),x86_64)
-        KBUILD_DEFCONFIG := x86_64_defconfig
-  else
+  ifeq ($(shell uname -m | sed -e 's/i.86/i386/'),i386)
         KBUILD_DEFCONFIG := i386_defconfig
+  else
+        KBUILD_DEFCONFIG := x86_64_defconfig
   endif
 else
         KBUILD_DEFCONFIG := $(ARCH)_defconfig