arm64: Remove signal translation and exec_domain

As execution domain support is gone we can remove
signal translation from the signal code and remove
exec_domain from thread_info.

Signed-off-by: Richard Weinberger <richard@nod.at>

arch/arm64/include/asm/thread_info.h

@@ -33,7 +33,6 @@
 #ifndef __ASSEMBLY__
 
 struct task_struct;
-struct exec_domain;
 
 #include <asm/types.h>
 
@@ -47,7 +46,6 @@ struct thread_info {
 	unsigned long		flags;		/* low level flags */
 	mm_segment_t		addr_limit;	/* address limit */
 	struct task_struct	*task;		/* main task structure */
-	struct exec_domain	*exec_domain;	/* execution domain */
 	int			preempt_count;	/* 0 => preemptable, <0 => bug */
 	int			cpu;		/* cpu */
 };
@@ -55,7 +53,6 @@ struct thread_info {
 #define INIT_THREAD_INFO(tsk)						\
 {									\
 	.task		= &tsk,						\
-	.exec_domain	= &default_exec_domain,				\
 	.flags		= 0,						\
 	.preempt_count	= INIT_PREEMPT_COUNT,				\
 	.addr_limit	= KERNEL_DS,					\