MLK-10059 arm: imx6sx: correct the num of the pcie regulator

MLK-10059 arm: imx6sx: correct the num of the pcie regulator

The orignal regulat num of the MPCIE_3V3 regulator is wrong,
change it to the correct one.
Otherwise, there would be the following warning when boot kernel.
WARNING: CPU: 0 PID: 1 at fs/sysfs/dir.c:52 sysfs_warn_dup+0x6c/0x8c()
sysfs: cannot create duplicate filename
'/devices/soc0/regulators.18/3.regulato'
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.24-01139-g690bd11 #166
[<80014e6c>] (unwind_backtrace) from [<800118ac>] (show_stack+0x10/0x14)
[<800118ac>] (show_stack) from [<806b0018>] (dump_stack+0x78/0xc0)
[<806b0018>] (dump_stack) from [<8002c1ec>]
(warn_slowpath_common+0x68/0x8c) [<8002c1ec>] (warn_slowpath_common)
from [<8002c240>] (warn_slowpath_fmt+0x30/0) [<8002c240>]
(warn_slowpath_fmt) from [<8012de80>] (sysfs_warn_dup+0x6c/0x8c)
[<8012de80>] (sysfs_warn_dup) from [<8012df28>]
(sysfs_create_dir_ns+0x88/0x98) [<8012df28>] (sysfs_create_dir_ns) from
[<80274be8>] (kobject_add_internal+0x9c) [<80274be8>]
(kobject_add_internal) from [<80274fe0>] (kobject_add+0x4c/0x98)
[<80274fe0>] (kobject_add) from [<80317bf0>] (device_add+0xe0/0x51c)
[<80317bf0>] (device_add) from [<804e2dd4>]
(of_platform_device_create_pdata+0x)
[<804e2dd4>] (of_platform_device_create_pdata) from [<804e2edc>]
(of_platform_b) [<804e2edc>] (of_platform_bus_create) from [<804e2f38>]
(of_platform_bus_create) [<804e2f38>] (of_platform_bus_create) from
[<804e3090>] (of_platform_populate+0) [<804e3090>]
(of_platform_populate) from [<80cf2d40>] (imx6sx_init_machine+0x38)
[<80cf2d40>] (imx6sx_init_machine) from [<80cde264>]
(customize_machine+0x1c/0x) [<80cde264>] (customize_machine) from
[<800088cc>] (do_one_initcall+0xe8/0x144) [<800088cc>] (do_one_initcall)
from [<80cdbc04>] (kernel_init_freeable+0x104/0x) [<80cdbc04>]
(kernel_init_freeable) from [<806abfb4>] (kernel_init+0x8/0xec)
[<806abfb4>] (kernel_init) from [<8000e5f8>] (ret_from_fork+0x14/0x3c)
---[ end trace f90dcd76c3b24ac8 ]---

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