arm: dss-common: don't use reset_gpio from omap4_panda_dvi_device

gpio reset info is passed to the tfp410 panel driver via the panel's platform
data struct 'tfp410_platform_data'. The tfp driver doesn't use the reset_gpio
field in the omap4_panda_dvi_device struct. Remove this field.

Signed-off-by: Archit Taneja <archit@ti.com>
Cc: Tony Lindgren <tony@atomide.com>