ENGR00253947 EPDC: fix reboot failure

ENGR00253947 EPDC: fix reboot failure

This patch is to

1) add clock enablement before access EPDC registers, otherwise system may hang.

And,
2) fix unbalanced disablement for PMIC regulators

------------[ cut here ]------------
WARNING: at drivers/regulator/core.c:1422 _regulator_disable+0xf8/0x12c()
unbalanced disables for VCOM
Modules linked in:
[<80040518>] (unwind_backtrace+0x0/0xf8) from [<800671d8>]
		(warn_slowpath_common +0x4c/0x64)
[<800671d8>] (warn_slowpath_common+0x4c/0x64) from [<80067284>]
		(warn_slowpath_fmt+0x30/0x40)
[<80067284>] (warn_slowpath_fmt+0x30/0x40) from [<8024ef60>]
		(_regulator_disable+0xf8/0x12c)
[<8024ef60>] (_regulator_disable+0xf8/0x12c) from [<8024efc4>]
		(regulator_disable+0x30/0x70)
[<8024efc4>] (regulator_disable+0x30/0x70) from [<80241044>]
		(mxc_epdc_fb_shutdown+0x18/0x84)
[<80241044>] (mxc_epdc_fb_shutdown+0x18/0x84) from [<80277f64>]
		(platform_drv_shutdown+0x18/0x1c)
[<80277f64>] (platform_drv_shutdown+0x18/0x1c) from [<802751d0>]
		(device_shutdown+0xac/0x124)
[<802751d0>] (device_shutdown+0xac/0x124) from [<8007812c>]
		(kernel_restart_prepare+0x30/0x38)
[<8007812c>] (kernel_restart_prepare+0x30/0x38) from [<80078140>]
		(kernel_restart+0xc/0x48)
[<80078140>] (kernel_restart+0xc/0x48) from [<80078290>]
		(sys_reboot+0x10c/0x1c4)
[<80078290>] (sys_reboot+0x10c/0x1c4) from [<8003ad40>]
		(ret_fast_syscall+0x0/0x30)
---[ end trace e392f5dd2f75e1a5 ]---
------------[ cut here ]------------
WARNING: at drivers/regulator/core.c:1422 _regulator_disable+0xf8/0x12c()
unbalanced disables for DISPLAY
Modules linked in:
[<80040518>] (unwind_backtrace+0x0/0xf8) from [<800671d8>]
		(warn_slowpath_common+0x4c/0x64)
[<800671d8>] (warn_slowpath_common+0x4c/0x64) from [<80067284>]
		(warn_slowpath_fmt+0x30/0x40)
[<80067284>] (warn_slowpath_fmt+0x30/0x40) from [<8024ef60>]
		(_regulator_disable+0xf8/0x12c)
[<8024ef60>] (_regulator_disable+0xf8/0x12c) from [<8024efc4>]
		(regulator_disable+0x30/0x70)
[<8024efc4>] (regulator_disable+0x30/0x70) from [<8024104c>]
		(mxc_epdc_fb_shutdown+0x20/0x84)
[<8024104c>] (mxc_epdc_fb_shutdown+0x20/0x84) from [<80277f64>]
		(platform_drv_shutdown+0x18/0x1c)
[<80277f64>] (platform_drv_shutdown+0x18/0x1c) from [<802751d0>]
		(device_shutdown+0xac/0x124)
[<802751d0>] (device_shutdown+0xac/0x124) from [<8007812c>]
		(kernel_restart_prepare+0x30/0x38)
[<8007812c>] (kernel_restart_prepare+0x30/0x38) from [<80078140>]
		(kernel_restart+0xc/0x48)
[<80078140>] (kernel_restart+0xc/0x48) from [<80078290>]
		(sys_reboot+0x10c/0x1c4)
[<80078290>] (sys_reboot+0x10c/0x1c4) from [<8003ad40>]
		(ret_fast_syscall+0x0/0x30)
---[ end trace e392f5dd2f75e1a6 ]---

Signed-off-by: Robby Cai <R63905@freescale.com>