xtensa: Return true/false (not 1/0) from bool function

Return boolean values ("true" or "false") instead of 1 or 0 from bool
function. This fixes the following warnings from coccicheck:

./arch/xtensa/kernel/traps.c:304:10-11: WARNING: return of 0/1 in
function 'check_div0' with return type bool
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Message-Id: <20220518230953.112266-1-yang.lee@linux.alibaba.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/kernel/traps.c

@@ -301,7 +301,7 @@ static bool check_div0(struct pt_regs *regs)
 
 	if (user_mode(regs)) {
 		if (copy_from_user(buf, (void __user *)regs->pc + 2, 5))
-			return 0;
+			return false;
 		p = buf;
 	} else {
 		p = (const u8 *)regs->pc + 2;