sparc64: fix prototypes of reads[bwl]()

Conventions for readsl() are the same as for readl() - any __iomem
pointer is acceptable, both const and volatile ones being OK. Same
for readsb() and readsw().

Signed-off-by: Al Viro <[e-mail]>
Reviewed-by: Andreas Larsson <[e-mail]>
Signed-off-by: Andreas Larsson <[e-mail]> # Making sparc64 subject prefix

arch/sparc/include/asm/io_64.h

···
 #define insw insw
 #define insl insl
 
-static inline void readsb(void __iomem *port, void *buf, unsigned long count)
+static inline void readsb(const volatile void __iomem *port, void *buf, unsigned long count)
 {
 	insb((unsigned long __force)port, buf, count);
 }
 #define readsb readsb
 
-static inline void readsw(void __iomem *port, void *buf, unsigned long count)
+static inline void readsw(const volatile void __iomem *port, void *buf, unsigned long count)
 {
 	insw((unsigned long __force)port, buf, count);
 }
 #define readsw readsw
 
-static inline void readsl(void __iomem *port, void *buf, unsigned long count)
+static inline void readsl(const volatile void __iomem *port, void *buf, unsigned long count)
 {
 	insl((unsigned long __force)port, buf, count);
 }