Bluetooth: Simplify / fix return values from tk_request

Bluetooth: Simplify / fix return values from tk_request

Some static checker run by 0day reports a variableScope warning.

net/bluetooth/smp.c:870:6: warning:
	The scope of the variable 'err' can be reduced. [variableScope]

There is no need for two separate variables holding return values.
Stick with the existing variable. While at it, don't pre-initialize
'ret' because it is set in each code path.

tk_request() is supposed to return a negative error code on errors,
not a bluetooth return code. The calling code converts the return
value to SMP_UNSPECIFIED if needed.

Fixes: 92516cd97fd4 ("Bluetooth: Always request for user confirmation for Just Works")
Cc: Sonny Sasaka <sonnysasaka@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Sonny Sasaka <sonnysasaka@chromium.org>
Signed-off-by: Sonny Sasaka <sonnysasaka@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>