soc: aspeed: Fix a reference leak in aspeed_socinfo_init()

This needs to call of_node_put(np) before returning if of_iomap() fails.

Fixes: e0218dca ("soc: aspeed: Add soc info driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20201113100850.GA168908@mwanda


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