drm/i915: remove always-defined CONFIG_AS_MOVNTDQA

CONFIG_AS_MOVNTDQA was introduced by commit 0b1de5d5 ("drm/i915:
Use SSE4.1 movntdqa to accelerate reads from WC memory").

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35 ("kbuild: Raise the minimum
required binutils version to 2.21").

I confirmed the code in $(call as-instr,...) can be assembled by the
binutils 2.21 assembler and also by LLVM integrated assembler.

Remove CONFIG_AS_MOVNTDQA, which is always defined.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/Makefile

@@ -28,9 +28,6 @@ subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
 CFLAGS_i915_pci.o = $(call cc-disable-warning, override-init)
 CFLAGS_display/intel_fbdev.o = $(call cc-disable-warning, override-init)
 
-subdir-ccflags-y += \
-	$(call as-instr,movntdqa (%eax)$(comma)%xmm0,-DCONFIG_AS_MOVNTDQA)
-
 subdir-ccflags-y += -I$(srctree)/$(src)
 
 # Please keep these build lists sorted!

drivers/gpu/drm/i915/i915_memcpy.c

@@ -35,7 +35,6 @@
 
 static DEFINE_STATIC_KEY_FALSE(has_movntdqa);
 
-#ifdef CONFIG_AS_MOVNTDQA
 static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len)
 {
 	kernel_fpu_begin();
@@ -93,10 +92,6 @@ static void __memcpy_ntdqu(void *dst, const void *src, unsigned long len)
 
 	kernel_fpu_end();
 }
-#else
-static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) {}
-static void __memcpy_ntdqu(void *dst, const void *src, unsigned long len) {}
-#endif
 
 /**
  * i915_memcpy_from_wc: perform an accelerated *aligned* read from WC