libpayload;arch,cpu/x86: drop USE_MARCH_586 Kconfig option

Only the Intel Quark SoC selected this option and that SoC was dropped
in commit 531023285e ("soc/intel/quark: Drop support"), so drop this
Kconfig option too.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ic4f1c7530cd8ac7a1945b1493a2d53a7904daa06
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75473
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

payloads/libpayload/Kconfig

@@ -167,14 +167,6 @@ config BASE_ADDRESS
 
 endmenu
 
-config USE_MARCH_586
-	bool "Use march=586 qualifier to build"
-	default n
-	depends on ARCH_X86
-	help
-	  Allow a platform or processor to select to be compiled using
-	  the '-march=i586' option instead of the typical '-march=i686'
-
 menu "Standard Libraries"
 
 config LIBC

src/arch/x86/Kconfig

@@ -92,12 +92,6 @@ config ARCH_X86_64_PGTBL_LOC
 	  The position where to place pagetables. Needs to be known at
 	  compile time. Must not overlap other files in CBFS.
 
-config USE_MARCH_586
-	def_bool n
-	help
-	  Allow a platform or processor to select to be compiled using
-	  the '-march=i586' option instead of the typical '-march=i686'
-
 # This is an SMP option. It relates to starting up APs.
 # It is usually set in mainboard/*/Kconfig.
 # TODO: Improve description.

src/cpu/x86/entry32.S

@@ -54,7 +54,6 @@ debug_spinloop:
 	jz	debug_spinloop
 #endif
 
-#if !CONFIG(USE_MARCH_586)
 	/* MMX registers required here */
 
 	/* BIST result in eax */
@@ -66,7 +65,6 @@ __timestamp:
 	rdtsc
 	movd	%eax, %mm1
 	movd	%edx, %mm2
-#endif
 
 #if CONFIG(SSE)
 enable_sse:

util/xcompile/xcompile

@@ -286,11 +286,7 @@ fi
 if [ "${TARCH}" = "x86_32" ]; then
 cat <<EOF
 
-ifneq (\$(CONFIG_USE_MARCH_586)\$(CONFIG_LP_USE_MARCH_586),)
-	CFLAGS_${TARCH} += -march=i586
-else
-	CFLAGS_${TARCH} += -march=i686
-endif
+CFLAGS_${TARCH} += -march=i686
 EOF
 fi