drivers: pcie_ep: iproc: ensure config and api are const

The `config` and `api` members of `struct device` are expected
to be `const`. This also improves reliability, as `config`
and `api` are stored in rom rather than ram, which has the
potential to be corrupted at runtime in the absense of an MMU.

Signed-off-by: Chris Friedt <[email protected]>
(cherry picked from commit 7212792)

Author: cfriedt

drivers/pcie/endpoint/pcie_ep_iproc.c

@@ -467,7 +467,7 @@ static int iproc_pcie_ep_init(const struct device *dev)
 
 static struct iproc_pcie_ep_ctx iproc_pcie_ep_ctx_0;
 
-static struct iproc_pcie_ep_config iproc_pcie_ep_config_0 = {
+static const struct iproc_pcie_ep_config iproc_pcie_ep_config_0 = {
 	.id = 0,
 	.base = (struct iproc_pcie_reg *)DT_INST_REG_ADDR(0),
 	.reg_size = DT_INST_REG_SIZE(0),
@@ -482,7 +482,7 @@ static struct iproc_pcie_ep_config iproc_pcie_ep_config_0 = {
 #endif
 };
 
-static struct pcie_ep_driver_api iproc_pcie_ep_api = {
+static const struct pcie_ep_driver_api iproc_pcie_ep_api = {
 	.conf_read = iproc_pcie_conf_read,
 	.conf_write = iproc_pcie_conf_write,
 	.map_addr = iproc_pcie_map_addr,