ARM: 8573/1: domain: move {set,get}_domain under config guard

Recursive undefined instrcution falut is seen with R-class taking an
exception. The reson for that is __show_regs() tries to get domain
information, but domains is not available on !MMU cores, like R/M
class.

Fix it by puting {set,get}_domain functions under CONFIG_CPU_CP15_MMU
guard and providing stubs for the case where domains is not supported.
Signed-off-by: NVladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/domain.h

@@ -84,6 +84,7 @@
 
 #ifndef __ASSEMBLY__
 
+#ifdef CONFIG_CPU_CP15_MMU
 static inline unsigned int get_domain(void)
 {
 	unsigned int domain;
@@ -103,6 +104,16 @@ static inline void set_domain(unsigned val)
 	  : : "r" (val) : "memory");
 	isb();
 }
+#else
+static inline unsigned int get_domain(void)
+{
+	return 0;
+}
+
+static inline void set_domain(unsigned val)
+{
+}
+#endif
 
 #ifdef CONFIG_CPU_USE_DOMAINS
 #define modify_domain(dom,type)					\