ARM: ixp4xx: remove compilation warnings in io.h

ARM: ixp4xx: remove compilation warnings in io.h

When arch/arm/mach-ixp4xx/common-pci.c is compiled, two warnings
occur:

arch/arm/mach-ixp4xx/include/mach/io.h:144: warning: passing argument 1 of '__raw_readb' makes pointer from integer without a cast
arch/arm/mach-ixp4xx/include/mach/io.h:79: warning: passing argument 2 of '__raw_writeb' makes pointer from integer without a cast

Both functions expect an 'volatile void __iomem *' but get an u32.
The 'u32 addr' variable is initialized with the address of an
'volatile void __iomem *' pointer. Passing the pointer
directly, avoids the warning and semantics are preserved.

This warning was found with vampyr.

Signed-off-by: Stefan Hengelein <stefan.hengelein@fau.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>