riscv: io.h: Add defines for reads/writes functions

Add defines for {read,write}s{b,w,l} functions to make asm-generic/io.h
aware of them.

Signed-off-by: Igor Prusov <ivprusov@salutedevices.com>
diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
index 4170877..cedd537 100644
--- a/arch/riscv/include/asm/io.h
+++ b/arch/riscv/include/asm/io.h
@@ -307,6 +307,14 @@
 		longlen--;
 	}
 }
+
+#define readsb readsb
+#define readsw readsw
+#define readsl readsl
+#define writesb writesb
+#define writesw writesw
+#define writesl writesl
+
 #endif
 
 #define outb_p(val, port)		outb((val), (port))