[PATCH] MIPS: fix duplicate define

[Sudip Mukherjee]

The mips build of ip27_defconfig is failing with the error:
In file included from ../arch/mips/include/asm/mach-ip27/spaces.h:29:0,
                 from ../arch/mips/include/asm/page.h:12,
                 from ../arch/mips/vdso/vdso.h:26,
                 from ../arch/mips/vdso/gettimeofday.c:11:
../arch/mips/include/asm/mach-generic/spaces.h:28:0:
	error: "CAC_BASE" redefined [-Werror]
 #define CAC_BASE  _AC(0x80000000, UL)
 
In file included from ../arch/mips/include/asm/page.h:12:0,
                 from ../arch/mips/vdso/vdso.h:26,
                 from ../arch/mips/vdso/gettimeofday.c:11:
../arch/mips/include/asm/mach-ip27/spaces.h:22:0:
	note: this is the location of the previous definition
 #define CAC_BASE  0xa800000000000000

Add a condition to check if CAC_BASE is already defined, and define it
only if it is not yet defined.

Fixes: 3ffc17d8768b ("MIPS: Adjust MIPS64 CAC_BASE to reflect Config.K0")
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
---

Build log is at:
https://travis-ci.org/sudipm-mukherjee/parport/jobs/174134289

 arch/mips/include/asm/mach-generic/spaces.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/mips/include/asm/mach-generic/spaces.h b/arch/mips/include/asm/mach-generic/spaces.h
index 952b0fd..61b75da 100644
--- a/arch/mips/include/asm/mach-generic/spaces.h
+++ b/arch/mips/include/asm/mach-generic/spaces.h
@@ -23,10 +23,12 @@
 
 #ifdef CONFIG_32BIT
 #ifdef CONFIG_KVM_GUEST
+#ifndef CAC_BASE
 #define CAC_BASE		_AC(0x40000000, UL)
 #else
 #define CAC_BASE		_AC(0x80000000, UL)
 #endif
+#endif
 #ifndef IO_BASE
 #define IO_BASE			_AC(0xa0000000, UL)
 #endif
-- 
1.9.1