PCI: brcmstb: Initialize "tmp" before use

The variable 'tmp' is used multiple times in the brcm_pcie_setup()
function.  One such usage did not initialize 'tmp' to the current value
of the target register.  By luck the mistake does not currently affect
behavior;  regardless 'tmp' is now initialized properly.
Suggested-by: Rafał Miłecki <zajec5@gmail.com>
Link: https://lore.kernel.org/r/20201102205712.23332-1-james.quinlan@broadcom.com
Fixes: c0452137 ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")
Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>

drivers/pci/controller/pcie-brcmstb.c

@@ -893,6 +893,7 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 		burst = 0x2; /* 512 bytes */
 
 	/* Set SCB_MAX_BURST_SIZE, CFG_READ_UR_MODE, SCB_ACCESS_EN */
+	tmp = readl(base + PCIE_MISC_MISC_CTRL);
 	u32p_replace_bits(&tmp, 1, PCIE_MISC_MISC_CTRL_SCB_ACCESS_EN_MASK);
 	u32p_replace_bits(&tmp, 1, PCIE_MISC_MISC_CTRL_CFG_READ_UR_MODE_MASK);
 	u32p_replace_bits(&tmp, burst, PCIE_MISC_MISC_CTRL_MAX_BURST_SIZE_MASK);