x86: move arch-specific asmlinkage to <asm/linkage.h>

Commit 65dd74a674d6 (x86: ivybridge: Implement SDRAM init) introduced
x86-specific asmlinkage into arch/x86/include/asm/config.h.

Commit ed0a2fbf14f7 (x86: Add a definition of asmlinkage) added the
same macro define again, this time, into include/common.h.
(Please do not add arch-specific stuff to include/common.h any more;
it is already too cluttered.)

The generic asmlinkage is defined in <linux/linkage.h>.  If you want
to override it with an arch-specific one, the best way is to add it
to <asm/linkage.h> like Linux Kernel.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/include/asm/arch-ivybridge/pei_data.h b/arch/x86/include/asm/arch-ivybridge/pei_data.h
index 5026c8b..9453336 100644
--- a/arch/x86/include/asm/arch-ivybridge/pei_data.h
+++ b/arch/x86/include/asm/arch-ivybridge/pei_data.h
@@ -7,6 +7,8 @@
 #ifndef ASM_ARCH_PEI_DATA_H
 #define ASM_ARCH_PEI_DATA_H
 
+#include <linux/linkage.h>
+
 struct pch_usb3_controller_settings {
 	/* 0: Disable, 1: Enable, 2: Auto, 3: Smart Auto */
 	uint16_t mode;