x86: unify CPU_TYPE for legacy and geode

According to some reports, -march=pentium-mmx is a better choice for
older Geode CPUs than -march=geode anyway.

Bump the minimum architecture of the legacy target from i486 to
pentium-mmx. Anything older is not worth supporting anyway.

Signed-off-by: Felix Fietkau <nbd@nbd.name>

include/target.mk

@@ -170,10 +170,9 @@ ifeq ($(DUMP),1)
     CPU_CFLAGS_octeon = -march=octeon -mabi=64
   endif
   ifeq ($(ARCH),i386)
-    CPU_TYPE ?= i486
-    CPU_CFLAGS_i486 = -march=i486
+    CPU_TYPE ?= pentium
+    CPU_CFLAGS_pentium = -march=pentium-mmx
     CPU_CFLAGS_pentium4 = -march=pentium4
-    CPU_CFLAGS_geode = -march=geode -mmmx -m3dnow
   endif
   ifneq ($(findstring arm,$(ARCH)),)
     CPU_TYPE ?= xscale

target/linux/x86/geode/target.mk

@@ -7,8 +7,6 @@ DEFAULT_PACKAGES += \
 			kmod-ledtrig-heartbeat kmod-ledtrig-gpio \
 			kmod-ledtrig-netdev hwclock wpad-mini
 
-CPU_TYPE := geode
-
 define Target/Description
 	Build firmware images for AMD Geode GX/LX based systems (net5501, alix, geos)
 endef