Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" a sysfs file.

Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Brian Starkey <brian.starkey@arm.com>
Cc: Mali DP Maintainers <malidp@foss.arm.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: NEmil Velikov <emil.l.velikov@gmail.com>
Tested-by: NLiviu Dudau <liviu.dudau@arm.com>
Acked-by: NLiviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200517193655.3895087-2-emil.l.velikov@gmail.com