Merge branch 'mlxsw-Support-for-shared-buffers-in-Spectrum-2'

Ido Schimmel says:

====================
mlxsw: Support for shared buffers in Spectrum-2

Petr says:

Spectrum-2 will be configured with a different set of pools than
Spectrum-1, their sizes will be larger, and the individual quotas will
be different as well. It is therefore necessary to make the shared
buffer module aware of this dependence on chip type, and adjust the
individual tables.

In patch #1, introduce a structure for keeping per-chip immutable and
default values.

In patch #2, structures for keeping current values of SBPM and SBPR
(pool configuration and port-pool quota) are allocated dynamically to
support varying pool counts.

In patches #3 to #7, uses of individual shared buffer configuration
tables are migrated from global definitions to fields in struct
mlxsw_sp_sb_vals, which was introduced above.

Up until this point, the actual configuration is still the one suitable
for Spectrum-1. In patch #8 Spectrum-2 configuration is added.

In patch #9, port headroom configuration is changed to take into account
current recommended value for a 100-Gbps port, and the split factor.

In patch #10, requests for overlarge headroom are rejected. This avoids
potential chip freeze should such overlarge requests be made.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>