fsi: aspeed: convert to devm_platform_ioremap_resource

Use devm_platform_ioremap_resource() to simplify code.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20191228190631.26777-1-tiny.windzz@gmail.com


Signed-off-by: Joel Stanley <joel@jms.id.au>