UPSTREAM: drm/rockchip: fix wrong pitch/size using on gem

UPSTREAM: drm/rockchip: fix wrong pitch/size using on gem

args->pitch and args->size may not be set by userspace, sometimes
userspace only malloc args and not memset args to zero, then
args->pitch and args->size is random, it is very danger to use
pitch/size on gem.

pitch's type is u32, and min_pitch's type is int, example,
pitch is 0xffffffff, then pitch < min_pitch return true, then gem will
alloc very very big bufffer, it would eat all the memory and cause kernel
crash.

Stop using pitch/size from args, calc them from other args.

Change-Id: I867d61bf6bc48a2989ae4d15a819a85a7e38d26f
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
(cherry picked from commit e3c4abdb3bc9b76bedd416ecc5c27633a2f8afed)