arch/Config.in.x86: consolidate Geode CPU targets

Since its introduction in 7d8a59b40, the BR2_x86_geode CPU target has
pointed to GCC -march=geode which targets AMD Geode processors [0].

This arch tuning enables MMX and 3DNow! extensions in GCC but these are
not currently reflected in the selected flags by BR2_x86_geode.

This is likely due to the confusing naming and history of "Geode".

The AMD Geode can trace its origins back to the Cyrix MediaGXm [1] and
then to the NSC Geode GXm/GXLV/GX1/GX2 [2]. All of these processors have
MMX instruction support listed in their datasheets. The NSC GX2 was the
first in the series to enable 3DNow!.

When 7fed07d3a4a introduced BR2_X86_CPU_HAS_MMX, Geode was skipped
presumably because it wasn't clear that the target is AMD Geode and
because the Wikipedia documentation for Geode is incomplete [2] with
regards to supported instructions as they all support MMX.

When f6cd56b9ce3 introduced BR2_X86_CPU_HAS_3DNOW, Geode was skipped
presumably for similar reasons.

Note: the in-tree olpc_xo1_defconfig uses BR2_x86_geode which is fine
as this hardware uses the AMD Geode [3].

Make it more clear that the target is AMD Geode by renaming the Kconfig
menu option and add both MMX and 3DNow! flags to BR2_x86_geode.

This also means that BR2_x86_geode_mmx is no longer needed, and can be
removed. No legacy handling is needed since BR2_x86_geode_mmx has
never been part of any release.

[0]: https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/i386/geode.md;;hb=HEAD
[1]: https://en.wikipedia.org/wiki/MediaGX#MediaGXm
[2]: https://en.wikipedia.org/wiki/Geode_%28processor%29
[3]: https://wiki.laptop.org/go/Hardware_specification

Signed-off-by: Vincent Fazio <vfazio@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

arch/Config.in.x86

@@ -705,22 +705,10 @@ config BR2_x86_zen4
 	select BR2_X86_CPU_HAS_AVX512
 	select BR2_ARCH_NEEDS_GCC_AT_LEAST_13
 config BR2_x86_geode
-	bool "geode (no mmx)"
-	depends on !BR2_x86_64
-	help
-	  For several variant of geode which have not MMX support.
-	  See https://en.wikipedia.org/wiki/Geode_%28processor%29 to
-	  determine if your particular Geode processor supports MMX or
-	  not.
-config BR2_x86_geode_mmx
-	bool "geode (with mmx)"
+	bool "AMD Geode"
 	depends on !BR2_x86_64
 	select BR2_X86_CPU_HAS_MMX
-	help
-	  For several variant of geode which have MMX support.
-	  See https://en.wikipedia.org/wiki/Geode_%28processor%29 to
-	  determine if your particular Geode processor supports MMX or
-	  not.
+	select BR2_X86_CPU_HAS_3DNOW
 config BR2_x86_c3
 	bool "Via/Cyrix C3 (Samuel/Ezra cores)"
 	depends on !BR2_x86_64