PCI: brcmstb: Assert fundamental reset on initialization

commit  a56dc666444062fe3cc568489cc68fc78bf9476c from
https://github.com/raspberrypi/linux.git rpi-5.4.y

commit 22e21e51 upstream.

While preparing the driver for upstream this detail was missed.

If not asserted during the initialization process, devices connected on
the bus will not be made aware of the internal reset happening. This,
potentially resulting in unexpected behavior.

Link: https://lore.kernel.org/r/20200507172020.18000-1-nsaenzjulienne@suse.de
Fixes: c0452137

 ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Meng Li <Meng.Li@windriver.com>