spi: aspeed: Add AST2700 SoC support and Quad SPI

Merge series from Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>:

This series adds AST2700 support to the ASPEED FMC/SPI driver and
bindings, introduces 64-bit address compatibility, and improves
Quad SPI page programming behavior. It also implements AST2700-specific
segment logic, where range adjustment is not required because the
AST2700 SPI hardware controller already fixes decoding issues on
the existing platforms and adopts an updated scheme.