treewide: remove unused archs leftovers

These are all unused by the current targets, clean up and stop
irritating the user with irrelevant grep results.

Signed-off-by: Andre Heider <a.heider@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/23240
Signed-off-by: Robert Marko <robimarko@gmail.com>

toolchain/Config.in

@@ -222,7 +222,6 @@ menuconfig TOOLCHAINOPTS
 menuconfig EXTRA_TARGET_ARCH
 	bool
 	prompt "Enable an extra toolchain target architecture" if TOOLCHAINOPTS
-	depends on !sparc
 	help
 	  Some builds may require a 'biarch' toolchain. This option
 	  allows you to specify an additional target arch.
@@ -298,7 +297,6 @@ comment "C Library"
 
 choice
 	prompt "C Library implementation" if TOOLCHAINOPTS
-	default LIBC_USE_GLIBC if arc
 	default LIBC_USE_MUSL
 	help
 	  Select the C library implementation.
@@ -310,7 +308,6 @@ choice
 	config LIBC_USE_MUSL
 		select USE_MUSL
 		bool "Use musl"
-		depends on !arc
 
 endchoice
 
@@ -356,11 +353,10 @@ config USE_LLVM_BUILD
 	bool
 
 config USE_GLIBC
-	default y if !TOOLCHAINOPTS && !EXTERNAL_TOOLCHAIN && !NATIVE_TOOLCHAIN && (arc)
 	bool
 
 config USE_MUSL
-	default y if !TOOLCHAINOPTS && !EXTERNAL_TOOLCHAIN && !NATIVE_TOOLCHAIN && !(arc)
+	default y if !TOOLCHAINOPTS && !EXTERNAL_TOOLCHAIN && !NATIVE_TOOLCHAIN
 	bool
 
 config SSP_SUPPORT

toolchain/gcc/common.mk

@@ -108,7 +108,6 @@ GCC_CONFIGURE:= \
 		$(call qstrip,$(CONFIG_EXTRA_GCC_CONFIG_OPTIONS)) \
 		$(if $(CONFIG_mips64)$(CONFIG_mips64el),--with-arch=mips64 \
 			--with-abi=$(call qstrip,$(CONFIG_MIPS64_ABI))) \
-		$(if $(CONFIG_arc),--with-cpu=$(CONFIG_CPU_TYPE)) \
 		$(if $(CONFIG_powerpc64), $(if $(CONFIG_USE_MUSL),--with-abi=elfv2)) \
 		--with-system-zlib=$(STAGING_DIR_HOST) \
 		--with-zstd=$(STAGING_DIR_HOST) \