xtensa: clean up excsave1 initialization

Use xtensa_set_sr instead of inline assembly.
Rename local variable exc_table in early_trap_init to avoid conflict
with per-CPU variable of the same name.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/traps.h

@@ -57,11 +57,11 @@ void do_unhandled(struct pt_regs *regs);
 /* Initialize minimal exc_table structure sufficient for basic paging */
 static inline void __init early_trap_init(void)
 {
-	static struct exc_table exc_table __initdata = {
+	static struct exc_table init_exc_table __initdata = {
 		.fast_kernel_handler[EXCCAUSE_DTLB_MISS] =
 			fast_second_level_miss,
 	};
-	__asm__ __volatile__("wsr  %0, excsave1\n" : : "a" (&exc_table));
+	xtensa_set_sr(&init_exc_table, excsave1);
 }
 
 void secondary_trap_init(void);

arch/xtensa/kernel/traps.c

@@ -372,8 +372,7 @@ __init trap_set_handler(int cause, xtensa_exception_handler *handler)
 
 static void trap_init_excsave(void)
 {
-	unsigned long excsave1 = (unsigned long)this_cpu_ptr(&exc_table);
-	__asm__ __volatile__("wsr  %0, excsave1\n" : : "a" (excsave1));
+	xtensa_set_sr(this_cpu_ptr(&exc_table), excsave1);
 }
 
 static void trap_init_debug(void)