am335xevm: use pull-up on 2nd SPI CS when no SPI-I2C bridge

When the 2nd SPI CS is not used, pull it high as this signal
is typically active low.  This prevents from selecting other
devices on the same SPI bus by mistake.

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>
pl_hardware: add NULL pointer test in plhw_is_init

Test if the plhw pointer is NULL in plhw_is_init to make it
more conveninent as a general way of determining whether the
structure has been initialised or not.

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>
modelffb: fix early clock configuration for SPI-I2C bridge

In modelffb_early_init, when the CONFIG_I2C_S1D135X1 is enabled,
also write the configuration to the REG_CLOCK_CONFIGURATION in
order to enable the SPI-I2C bridge.  This fixes cold boot timeouts.

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>
modelffb.c: remove dead macros about SPI pads

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>
pl_hardware: fix delay when powering HB Z6 or Z7 off

Move the 150ms delay from plhw_disable to to plhw_static_free
as this is when the power is completely turned off (3.3V).  It
takes some time for the capacitors to discharge, and it can
cause some errors in the HV-PMIC to turn it back on again too
soon.

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>
modelffb: fix a few things in init/exit code

* move plhw_static_free to the end of modelffb_remove as it
  should be done only once when the module is removed

* fix failure handling in modelffb_modelf_init (goto
  free_regulator)

* only call modelffb_regulator_exit in modelffb_remove if the
  driver initialisation succeeded, otherwise it is already
  cleaned-up

* move destroy_workqyeye(parinfo->workqueue) higher in
  modelffb_remove to fix crashes when the driver is being removed
  in the middle of a display update or pending any delayed work

+ add 2014 to the copyright statement

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>