ACPI/IORT: Rename iort_node_map_rid() to make it generic

iort_node_map_rid() was designed to take an input id (that is not
necessarily a PCI requester id) and map it to an output id (eg an SMMU
streamid or an ITS deviceid) according to the mappings provided by an
IORT node mapping entries. This means that the iort_node_map_rid() input
id is not always a PCI requester id as its name, parameters and local
variables suggest, which is misleading.

Apply the s/rid/id substitution to the iort_node_map_rid() mapping
function and its users to make sure its intended usage is clearer.

Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Wei Xu <xuwei5@hisilicon.com>
Tested-by: Sinan Kaya <okaya@codeaurora.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Tomasz Nowicki <tn@semihalf.com>