s390/pci: define read*_relaxed functions

Just map the read*_relaxed() functions to their corresponding read*() functions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/io.h b/arch/s390/include/asm/io.h
index 16c3eb1..27cb321 100644
--- a/arch/s390/include/asm/io.h
+++ b/arch/s390/include/asm/io.h
@@ -85,6 +85,11 @@
 #define __raw_writel	zpci_write_u32
 #define __raw_writeq	zpci_write_u64
 
+#define readb_relaxed	readb
+#define readw_relaxed	readw
+#define readl_relaxed	readl
+#define readq_relaxed	readq
+
 #endif /* CONFIG_PCI */
 
 #include <asm-generic/io.h>