refactor(sgi): rewrite address space size definitions

The value of the macro CSS_SGI_REMOTE_CHIP_MEM_OFFSET can be different
across all the Neoverse reference design platforms. This value depends
on the number of address bits used per chip. So let all platforms define
CSS_SGI_ADDR_BITS_PER_CHIP which specifies the number of address bits
used per chip.

In addition to this, reuse the definition of CSS_SGI_ADDR_BITS_PER_CHIP
for single chip platforms and CSS_SGI_REMOTE_CHIP_MEM_OFFSET for multi-
chip platforms to determine the maximum address space size. Also,
increase the RD-N2 multi-chip address space per chip from 4TB to 64TB.

Signed-off-by: Vijayenthiran Subramaniam <vijayenthiran.subramaniam@arm.com>
Change-Id: If5e69ec26c2389304c71911729d4addbdf8b2686
7 files changed