arm: dts: rockchip: rock-5b: add support for PCIe3 and NVMe

this patch adds support for PCIe3 (M.2 M key) and enables NVMe.

 => pci
 BusDevFun  VendorId   DeviceId   Device Class       Sub-Class
 _____________________________________________________________
 00.00.00   0x1d87     0x3588     Bridge device           0x04
 01.00.00   0x10ec     0x8125     Network controller      0x00
 02.00.00   0x1d87     0x3588     Bridge device           0x04
 03.00.00   0x1179     0x011a     Mass storage controller 0x08
 => nvme scan
 => nvme info
 Device 0: Vendor: 0x1179 Rev: AGHA4101 Prod: 79CA20WPKRYN
             Type: Hard Disk
             Capacity: 488386.3 MB = 476.9 GB (1000215216 x 512)

Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>