simplebus: Map SYS_RES_IOPORT to SYS_RES_MEMORY later in alloc_resource

Specifically, the set/get_resource methods do not currently remap
resource types, so remap the type in alloc_resource only after
looking for a matching resource list entry.

Fixes: 3cf553288b96 simplebus: Consistently map SYS_RES_IOPORT to SYS_RES_MEMORY