ARM: dts: armada-38x: enable buffer manager support on Armada 38x boards

Since mvneta driver supports using hardware buffer management (BM), in
order to use it, board files have to be adjusted accordingly. This commit
enables BM on:
* A385-DB-AP - each port has its own pool for long and common pool for
short packets,
* A388-ClearFog - same as above,
* A388-DB - to each port unique 'short' and 'long' pools are mapped,
* A388-GP - same as above.

Moreover appropriate entry is added to 'soc' node ranges, as well as "okay"
status for 'bm' and 'bm-bppi' (internal SRAM) nodes.

[gregory.clement@free-electrons.com: add suppport for the ClearFog board]

Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>