xtensa: drop fast_syscall_kernel

There must be no xtensa-specific syscalls from the kernel code: register
spilling uses call+entry sequence and atomics have proper function
implementations. Drop fast_syscall_xtensa.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/kernel/entry.S

@@ -1022,25 +1022,6 @@ ENDPROC(fast_alloca)
  *   excsave_1:	dispatch table
  */
 
-ENTRY(fast_syscall_kernel)
-
-	/* Skip syscall. */
-
-	rsr	a0, epc1
-	addi	a0, a0, 3
-	wsr	a0, epc1
-
-	l32i	a0, a2, PT_DEPC
-	bgeui	a0, VALID_DOUBLE_EXCEPTION_ADDRESS, fast_syscall_unrecoverable
-
-	rsr	a0, depc			# get syscall-nr
-	_beqz	a0, fast_syscall_spill_registers
-	_beqi	a0, __NR_xtensa, fast_syscall_xtensa
-
-	j	kernel_exception
-
-ENDPROC(fast_syscall_kernel)
-
 ENTRY(fast_syscall_user)
 
 	/* Skip syscall. */

arch/xtensa/kernel/traps.c

@@ -51,7 +51,6 @@
 extern void kernel_exception(void);
 extern void user_exception(void);
 
-extern void fast_syscall_kernel(void);
 extern void fast_syscall_user(void);
 extern void fast_alloca(void);
 extern void fast_unaligned(void);
@@ -89,7 +88,6 @@ typedef struct {
 static dispatch_init_table_t __initdata dispatch_init_table[] = {
 
 { EXCCAUSE_ILLEGAL_INSTRUCTION,	0,	   do_illegal_instruction},
-{ EXCCAUSE_SYSTEM_CALL,		KRNL,	   fast_syscall_kernel },
 { EXCCAUSE_SYSTEM_CALL,		USER,	   fast_syscall_user },
 { EXCCAUSE_SYSTEM_CALL,		0,	   system_call },
 /* EXCCAUSE_INSTRUCTION_FETCH unhandled */