gpu: drm: radeon: cik: Replace mdelay() with msleep() in cik_pcie_gen3_enable()

cik_pcie_gen3_enable() is never called in atomic context.
It calls mdelay() to busily wait, which is not necessary.
mdelay() can be replaced with msleep().

This is found by a static analysis tool named DCNS written by myself.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/cik.c

@@ -9600,7 +9600,7 @@ static void cik_pcie_gen3_enable(struct radeon_device *rdev)
 				tmp |= LC_REDO_EQ;
 				WREG32_PCIE_PORT(PCIE_LC_CNTL4, tmp);
 
-				mdelay(100);
+				msleep(100);
 
 				/* linkctl */
 				pci_read_config_word(root, bridge_pos + PCI_EXP_LNKCTL, &tmp16);