[Edgecore][as7946_30xb] Add new platform

[JakeLin-EC]

CPU: Intel Broadwell-DE Xeon 1548, 8-core MAC: Broadcom BCM88823 BMC: AST2600 CPLD: Intel 5M1270ZF256C5N (2pcs, FBGA256 package) Ethernet Port: 4 x 400G QSFP-DD (also support high power 100G optics) 22 x 100G QSFP28 4 x 25G SFP28 Power Supply: AC/DC or DC/DC max 1300W output, 1 + 1 redundant load-sharing Cooling: 5pcs hot swappable 6076, 12V fan, support 4 + 1 mode Dimension: 440mm (Width) x 480mm (Depth) x 87 mm (Height)

Signed-off-by: Jake Lin [email protected]