x86: cache.h: Add default for CONFIG_SYS_CACHELINE_SIZE

Don't just define ARCH_DMA_MINALIGN but also CONFIG_SYS_CACHELINE_SIZE
if it's undefined. This is needed for the xhci driver to compile.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/include/asm/cache.h b/arch/x86/include/asm/cache.h
index 508b63f..4ff63c3 100644
--- a/arch/x86/include/asm/cache.h
+++ b/arch/x86/include/asm/cache.h
@@ -11,12 +11,12 @@
  * If CONFIG_SYS_CACHELINE_SIZE is defined use it for DMA alignment.  Otherwise
  * use 64-bytes, a safe default for x86.
  */
-#ifdef CONFIG_SYS_CACHELINE_SIZE
-#define ARCH_DMA_MINALIGN	CONFIG_SYS_CACHELINE_SIZE
-#else
-#define ARCH_DMA_MINALIGN	64
+#ifndef CONFIG_SYS_CACHELINE_SIZE
+#define CONFIG_SYS_CACHELINE_SIZE	64
 #endif
 
+#define ARCH_DMA_MINALIGN		CONFIG_SYS_CACHELINE_SIZE
+
 static inline void wbinvd(void)
 {
 	asm volatile ("wbinvd" : : : "memory");