x86: Remove toolchain check for X32 ABI capability

Commit 0bf6276392e9 ("x32: Warn and disable rather than error if
binutils too old") added a small test in arch/x86/Makefile because
binutils 2.22 or newer is needed to properly support elf32-x86-64. This
check is no longer necessary, as the minimum supported version of
binutils is 2.23, which is enforced at configuration time with
scripts/min-tool-version.sh.

Remove this check and replace all uses of CONFIG_X86_X32 with
CONFIG_X86_X32_ABI, as two symbols are no longer necessary.

[nathan: Rebase, fix up a few places where CONFIG_X86_X32 was still
         used, and simplify commit message to satisfy -tip requirements]

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220314194842.3452-2-nathan@kernel.org
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 870e0d10..b903bfc 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2861,7 +2861,7 @@
 	help
 	  Support old a.out binaries in the 32bit emulation.
 
-config X86_X32
+config X86_X32_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
 	help
@@ -2870,10 +2870,6 @@
 	  full 64-bit register file and wide data path while leaving
 	  pointers at 32 bits for smaller memory footprint.
 
-	  You will need a recent binutils (2.22 or later) with
-	  elf32_x86_64 support enabled to compile a kernel with this
-	  option set.
-
 config COMPAT_32
 	def_bool y
 	depends on IA32_EMULATION || X86_32
@@ -2882,7 +2878,7 @@
 
 config COMPAT
 	def_bool y
-	depends on IA32_EMULATION || X86_X32
+	depends on IA32_EMULATION || X86_X32_ABI
 
 if COMPAT
 config COMPAT_FOR_U64_ALIGNMENT