x86: theadorable-x86-common: Change pci hotplug cmdline parameters (again)

This is needed for the PCIe hotplug to work correctly on some boards
with the newer Linux kernel versions.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>