MIPS: IP28: Fix/clean spaces.h

Broken values for UNCAC_BASE/IO_BASE caused complete breakage of IP28
builds. Only set special PHY_OFFSET and take everything else from
generic spaces.h
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7549/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 81832d7e7962a40d08d9fe2e7e71b7887bc30097)

arch/mips/include/asm/mach-ip28/spaces.h

@@ -11,15 +11,8 @@
 #ifndef _ASM_MACH_IP28_SPACES_H
 #define _ASM_MACH_IP28_SPACES_H
 
-#define CAC_BASE	_AC(0xa800000000000000, UL)
-
-#define HIGHMEM_START	(~0UL)
-
 #define PHYS_OFFSET	_AC(0x20000000, UL)
 
-#define UNCAC_BASE	_AC(0xc0000000, UL)     /* 0xa0000000 + PHYS_OFFSET */
-#define IO_BASE		UNCAC_BASE
-
 #include <asm/mach-generic/spaces.h>
 
 #endif /* _ASM_MACH_IP28_SPACES_H */