ENGR00240740-3 IPUv3 fb:Workaround bootup ipu error

ENGR00240740-3 IPUv3 fb:Workaround bootup ipu error

Enabling IPU hsp clock in mxcfb_probe() context by calling
ipu_init_channel() can avoid the IPU display channel(setup
in bootloader) from being damaged by some IPU common driver
APIS which enable/disable IPU hsp clock when doing driver
probe. However, somehow, after LDO bypass patch set is pushed
to kernel, this clock enablement can trigger IPU errors
(IPU_INT_STAT_5 - 0x00800000/IPU_INT_STAT_10 - 0x00100000) and
a display flash. A workaround is to enable IPU hsp clock when
we are at ipu_probe() context, which is earlier than mxcfb_probe()
context, and then to disable(cleanup) the clock once more when
fb_set_par() is triggered by the user for the first time. This
patch updates the comment for ipu_init_channel() and
ipu_enable_channel() in mxcfb_probe() context, and disables ipu
hsp clock when fb_set_par() is triggered by the user for the first
time.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
(cherry picked from commit 5528e415659a60f3c6d67db96692befb3302a58a)