ENGR00298389 pcie: let rc can access mem of ep

ENGR00298389 pcie: let rc can access mem of ep

- setup one new outbound memory region at rc side, used
to let imx6 pcie rc can access the memory of imx6 pcie ep
in imx6 pcie rc ep validation system.
- set the default address of the ddr memory to be 0x4000_0000

NOTE:
- default address 0x4000_0000 of ep side would be
accessed in this demo.
Test howto:
step1:
EP side:
1.1:
echo 0x40000000 > /sys/devices/soc0/soc.1/1ffc000.pcie/ep_bar0_addr

1.2:
memtool -32 0x40000000 4
E
Reading 0x4 count starting at address 0x40000000

0x40000000:  6FE9E9F6 7583FBB9 39EAEFEA FBDCFD78

step2:
RC side:
memtool -32 0x01000000=58D454DA
memtool -32 0x01000004=7332095B

step3:
EP side:
memtool -32 0x40000000 4
E
Reading 0x4 count starting at address 0x40000000

0x40000000:  58D454DA 7332095B 39EAEFEA FBDCFD78

Signed-off-by: Richard Zhu <r65037@freescale.com>