nvme: Fix getting PCI vendor id of the NVMe block device

nvme: Fix getting PCI vendor id of the NVMe block device

The codes currently try to read PCI vendor id of the NVMe block
device by dm_pci_read_config16() with its parameter set as its
root complex controller (ndev->pdev) instead of itself. This is
seriously wrong. We can read the vendor id by passing the correct
udevice parameter to the dm_pci_read_config16() API, however there
is a shortcut by reading the cached vendor id from the PCI device's
struct pci_child_platdata.

While we are here fixing this bug, apparently the quirk stuff handle
codes in nvme_get_info_from_identify() never takes effect since its
logic has never been true at all. Remove these codes completely.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>