[MIPS] PB1100: Fix pile of warnings

  CC      arch/mips/au1000/pb1100/board_setup.o
arch/mips/au1000/pb1100/board_setup.c: In function ‘board_setup’:
arch/mips/au1000/pb1100/board_setup.c:104: warning: passing argument 1 of ‘readb’ makes pointer from integer without a cast
arch/mips/au1000/pb1100/board_setup.c:105: warning: passing argument 1 of ‘readb’ makes pointer from integer without a cast
arch/mips/au1000/pb1100/board_setup.c:105: warning: passing argument 2 of ‘writeb’ makes pointer from integer without a cast
arch/mips/au1000/pb1100/board_setup.c:109: warning: passing argument 1 of ‘readb’ makes pointer from integer without a cast
arch/mips/au1000/pb1100/board_setup.c:110: warning: passing argument 1 of ‘readb’ makes pointer from integer without a cast
arch/mips/au1000/pb1100/board_setup.c:110: warning: passing argument 2 of ‘writeb’ makes pointer from integer without a cast
arch/mips/au1000/pb1100/board_setup.c:51: warning: unused variable ‘sys_clksrc’
arch/mips/au1000/pb1100/board_setup.c:51: warning: unused variable ‘sys_freqctrl’
arch/mips/au1000/pb1100/board_setup.c:50: warning: unused variable ‘pin_func’
    
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>