usb: host: max3421-hcd: Remove pdata test in max3421_hub_control()

We do not have to test if platform_data pointer is null in
max3421_hub_control(), as the driver probe will fail if no
platform_data is found.

Fixes: 721fdc83 ("usb: max3421: Add devicetree support")
Signed-off-by: Jules Maselbas <jules.maselbas@grenoble-inp.org>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>