ARM: mvebu: Fix kernel hang in mvebu_soc_id_init() when of_iomap failed

ARM: mvebu: Fix kernel hang in mvebu_soc_id_init() when of_iomap failed

commit dc4910d9e93f8cc56b190dd8fc9e789135978216 upstream.

When pci_base is accessed whereas it has not been properly mapped by
of_iomap() the kernel hang. The check of this pointer made an improper
use of IS_ERR() instead of comparing to NULL. This patch fix this
issue.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reported-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Fixes: 930ab3d403ae (i2c: mv64xxx: Add I2C Transaction Generator support)
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>