misc: hisi_hikey_usb: use PTR_ERR_OR_ZERO

Coccinelle suggested using PTR_ERR_OR_ZERO() and looking at the code,
we can use PTR_ERR_OR_ZERO() instead of checking IS_ERR() and then
doing 'return 0'.

Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Link: https://lore.kernel.org/r/20201026180026.3350-1-sudipm.mukherjee@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>