parisc: rename default_defconfig to defconfig

'default_defconfig' is an awkward name since 'defconfig' is the default.
Let's simply say 'defconfig' like other architectures. You can drop the
KBUILD_DEFCONFIG define by following the standard naming.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Helge Deller <deller@gmx.de>

arch/parisc/Makefile

@@ -19,8 +19,6 @@
 
 KBUILD_IMAGE := vmlinuz
 
-KBUILD_DEFCONFIG := default_defconfig
-
 NM		= sh $(srctree)/arch/parisc/nm
 CHECKFLAGS	+= -D__hppa__=1
 LIBGCC		= $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)