cnss2: Save default config space without BME enabled

BME should be enabled after config space has been restored. Make
sure the default config space saved which is restored during PCIe
link down recovery doesn't have BME enabled.

Change-Id: I227d09620128cbb3232f63a026bc6eb789a0b70c
Signed-off-by: Yue Ma <yuem@codeaurora.org>