usb: phy: msm: change devm_ioremap() to devm_ioremap_resource()

There are several issues here:
1) platform_get_resource() can return NULL and that wasn't handled.
2) We should request the memory before we remap it, and
   devm_ioremap_resource() does that.
3) devm_ioremap() returns a NULL but we were checking for IS_ERR().

Fixes: 6b99c68ec1f9 ('usb: phy: msm: Migrate to Managed Device Resource allocation')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>