PCI: brcmstb: Replace open coded value with PCIE_T_RRS_READY_MS

The delay that we are waiting on in brcm_pcie_start_link() is
PCIE_T_RRS_READY_MS, use it.

Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
[mani: Removed the redundant comment]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20250624231923.990361-3-florian.fainelli@broadcom.com

Author: ffainelli

drivers/pci/controller/pcie-brcmstb.c

@@ -1358,11 +1358,7 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie)
 	if (ret)
 		return ret;
 
-	/*
-	 * Wait for 100ms after PERST# deassertion; see PCIe CEM specification
-	 * sections 2.2, PCIe r5.0, 6.6.1.
-	 */
-	msleep(100);
+	msleep(PCIE_T_RRS_READY_MS);
 
 	/*
 	 * Give the RC/EP even more time to wake up, before trying to