spi: aspeed: Only map necessary address window region

spi: aspeed: Only map necessary address window region

Previously, the driver mapped the entire SPI address decoding region during
probe. On systems with small flash or limited memory, this could lead to
excessive memory usage or allocation failures.

This patch changes the strategy to initially map a small address window
for SPI flash device probing. After determining each chip select's flash
size, the driver unmaps the temporary region and remaps only the required
address window accordingly.

Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
Link: https://patch.msgid.link/20251001112605.1130723-7-chin-ting_kuo@aspeedtech.com
Signed-off-by: Mark Brown <broonie@kernel.org>