USB: apple-mfi-fastcharge: Fix kfree after failed kzalloc

kfree don't need to be called after a failed kzalloc

Signed-off-by: Lucas Tanure <tanure@linux.com>
Link: https://lore.kernel.org/r/20201115102837.331335-1-tanure@linux.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>