bcma: fix incorrect update of BCMA_CORE_PCI_MDIO_DATA

BugLink: https://bugs.launchpad.net/bugs/1864773

[ Upstream commit 420c20be ]

An earlier commit re-worked the setting of the bitmask and is now
assigning v with some bit flags rather than bitwise or-ing them
into v, consequently the earlier bit-settings of v are being lost.
Fix this by replacing an assignment with the bitwise or instead.

Addresses-Coverity: ("Unused value")
Fixes: 2be25cac ("bcma: add constants for PCI and use them")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/bcma/driver_pci.c

@@ -78,7 +78,7 @@ static u16 bcma_pcie_mdio_read(struct bcma_drv_pci *pc, u16 device, u8 address)
 		v |= (address << BCMA_CORE_PCI_MDIODATA_REGADDR_SHF_OLD);
 	}
 
-	v = BCMA_CORE_PCI_MDIODATA_START;
+	v |= BCMA_CORE_PCI_MDIODATA_START;
 	v |= BCMA_CORE_PCI_MDIODATA_READ;
 	v |= BCMA_CORE_PCI_MDIODATA_TA;
 
@@ -121,7 +121,7 @@ static void bcma_pcie_mdio_write(struct bcma_drv_pci *pc, u16 device,
 		v |= (address << BCMA_CORE_PCI_MDIODATA_REGADDR_SHF_OLD);
 	}
 
-	v = BCMA_CORE_PCI_MDIODATA_START;
+	v |= BCMA_CORE_PCI_MDIODATA_START;
 	v |= BCMA_CORE_PCI_MDIODATA_WRITE;
 	v |= BCMA_CORE_PCI_MDIODATA_TA;
 	v |= data;