drm/sun4i: tcon: Delete an error message in sun4i_tcon_init_irq()

The function “platform_get_irq” can log an error already.
Thus omit a redundant message for the exception handling in the
calling function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/5a6cf5a7-3f27-5425-4d6a-550a17bc51e3@web.de