sparc: implement is_32bit_task

We are currently embedding the same check from thread_info.h into
syscall.h thanks to the way syscall_get_arch() was implemented in the
audit tree.  Instead create a new function, is_32bit_task() which is
similar to that found on the powerpc arch.  This simplifies the
syscall.h code and makes the build/Kconfig requirements much easier
to understand.

Signed-off-by: Eric Paris <eparis@redhat.com
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: sparclinux@vger.kernel.org

arch/sparc/include/asm/syscall.h

@@ -128,12 +128,7 @@ static inline void syscall_set_arguments(struct task_struct *task,
 
 static inline int syscall_get_arch(void)
 {
-#if defined(__sparc__) && defined(__arch64__)
-	return test_thread_flag(TIF_32BIT) ? AUDIT_ARCH_SPARC
-					   : AUDIT_ARCH_SPARC64;
-#else
-	return AUDIT_ARCH_SPARC;
-#endif
+	return is_32bit_task() ? AUDIT_ARCH_SPARC : AUDIT_ARCH_SPARC64;
 }
 
 #endif /* __ASM_SPARC_SYSCALL_H */