configs: rk3568-pcie-ep: Reduce code size

Decrease SPI Flash support devices.

Change-Id: Ia44ab8be5dcf47e8af833685cec3aaceb0dfac6b
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>

config: Add rk3568 pcie ep config

Change-Id: I233d99542b5dba96fbde3eaeb97a451819fb9c20
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>