[MIPS] Rename CONFIG_BUILD_ELF64 into KBUILD_64BIT_SYM32

This patch renames it for 3 reasons:

    - "CONFIG" pattern is used by Kconfig. Now this macro is
      no more defined by Kconfig but by Kbuild itself make this
      clear by translating "CONFIG" into "KBUILD".

    - "ELF32" word is improper because it is irrelevant to ELF
      format and it makes confusion with CONFIG_BOOT_ELF32. So
      translate it with SYM32.

    - Add "64BIT" part to make clear that this macro implies a
      64 bits kernel.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/include/asm-mips/stackframe.h b/include/asm-mips/stackframe.h
index ed33366..59334f5 100644
--- a/include/asm-mips/stackframe.h
+++ b/include/asm-mips/stackframe.h
@@ -91,14 +91,14 @@
 #else
 		MFC0	k0, CP0_CONTEXT
 #endif
-#if defined(CONFIG_BUILD_ELF64) || (defined(CONFIG_64BIT) && __GNUC__ < 4)
+#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
+		lui	k1, %hi(kernelsp)
+#else
 		lui	k1, %highest(kernelsp)
 		daddiu	k1, %higher(kernelsp)
 		dsll	k1, 16
 		daddiu	k1, %hi(kernelsp)
 		dsll	k1, 16
-#else
-		lui	k1, %hi(kernelsp)
 #endif
 		LONG_SRL	k0, PTEBASE_SHIFT
 		LONG_ADDU	k1, k0
@@ -116,14 +116,14 @@
 		.endm
 #else
 		.macro	get_saved_sp	/* Uniprocessor variation */
-#if defined(CONFIG_BUILD_ELF64) || (defined(CONFIG_64BIT) && __GNUC__ < 4)
+#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
+		lui	k1, %hi(kernelsp)
+#else
 		lui	k1, %highest(kernelsp)
 		daddiu	k1, %higher(kernelsp)
 		dsll	k1, k1, 16
 		daddiu	k1, %hi(kernelsp)
 		dsll	k1, k1, 16
-#else
-		lui	k1, %hi(kernelsp)
 #endif
 		LONG_L	k1, %lo(kernelsp)(k1)
 		.endm