ide: include <asm/ide.h> only when needed

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/tx4939ide.c b/drivers/ide/tx4939ide.c
index 40b0812..fb037a5 100644
--- a/drivers/ide/tx4939ide.c
+++ b/drivers/ide/tx4939ide.c
@@ -18,6 +18,8 @@
 #include <linux/io.h>
 #include <linux/scatterlist.h>
 
+#include <asm/ide.h>
+
 #define MODNAME	"tx4939ide"
 
 /* ATA Shadow Registers (8-bit except for Data which is 16-bit) */