omap-serial: Fix the error handling in the omap_serial probe

The patch does the following

- The pm_runtime_disable is called in the remove not in the error
  case of probe.The patch calls the pm_runtime_disable in the error
  case.
- Calls pm_runtime_put in the error case.
- The  up is not freed in the error path. Fix the memory leak by using
  devm_* so that the memory need not be freed in the driver.
- Also the iounmap is not called fix the same by calling using devm_ioremap.
- Make the name of the error tags more meaningful.

Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>