powerpc: ppc4xx: canyonlands: config: Tidy up CONFIGs and config.mk

Many CONFIG options have an unnecessary value of 1. CONFIG_440 is set in
the various board config files. Also simplify the CONFIG_440 check in
config.mk

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/ppc4xx/config.mk b/arch/powerpc/cpu/ppc4xx/config.mk
index f87c9dc..9cb41bb 100644
--- a/arch/powerpc/cpu/ppc4xx/config.mk
+++ b/arch/powerpc/cpu/ppc4xx/config.mk
@@ -7,10 +7,7 @@
 
 PLATFORM_CPPFLAGS += -mstring -msoft-float
 
-cfg=$(srctree)/include/configs/$(CONFIG_SYS_CONFIG_NAME:"%"=%).h
-is440:=$(shell grep CONFIG_440 $(cfg))
-
-ifneq (,$(findstring CONFIG_440,$(is440)))
+ifneq (,$(CONFIG_440))
 PLATFORM_CPPFLAGS += -Wa,-m440 -mcpu=440
 else
 PLATFORM_CPPFLAGS += -Wa,-m405 -mcpu=405