octeontx2-pcicons: remove dev_err() from TTY write

commit f2ab142124f47e49f0af5c59a424f9aad87ed5e7 from
git@git.assembla.com:cavium/WindRiver.linux.git

Under the hood dev_err() calls printk(). When the time comes
to flush the buffer to the hardware, printk() iterates through
system consoles and calls their .write() handlers. Thus, calling
dev_err() in the TTY write handler results in calling the same
handler again from itself. That, in turn, leads to a deadlock.

Using trace_printk() instead allows to observe debug messages without
automatically writing them to console. If kernel is compiled without
tracing options, trace_printk() calls are not effective. After kernel
is built with the following options:

  CONFIG_FUNCTION_TRACER
  CONFIG_FUNCTION_GRAPH_TRACER
  CONFIG_STACK_TRACER
  CONFIG_DYNAMIC_FTRACE

Debug messages can be observed as follows (output truncated for
readability):

  ~# mount -t debugfs none /sys/kernel/debug/
  ~# cd /sys/kernel/debug/tracing/
  tracing# echo nop > current_tracer
  tracing# cat trace | head -15
  # tracer: nop
  #
  # entries-in-buffer/entries-written: 308/308   #P:1
  #
  #                  _-----=> irqs-off
  #                 / _----=> need-resched
  #                | / _---=> hardirq/softirq
  #                || / _--=> preempt-depth
  #                ||| /     delay
  # TASK-PID CPU#  |||| TIMESTAMP  FUNCTION
  #    | |     |   ||||    |         |
   dmesg-163 [000] d..1 121.11864: otx_console_write: Timeout awaiting host

Change-Id: Ia8daf4a695171583bc5c899fd9f99372d3819fed
Signed-off-by: Wojciech Zmuda <wzmuda@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/86224


Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>
Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>