ARM: dts: aspeed: tacoma: Remove duplicate flash nodes

This is a revert of "ARM: dts: aspeed: tacoma: Enable FMC and SPI
devices" which was already applied as part of "ARM: dts: aspeed: Add
Tacoma machine".

Fixes: 8737481e ("ARM: dts: aspeed: tacoma: Enable FMC and SPI devices")
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>