drm/msm: Fix wrong size calculation

stable inclusion
from stable-v5.10.96
commit 82c310d04b0fdd48dfece56a4186f5d0940185d8
bugzilla: https://gitee.com/openeuler/kernel/issues/I55NWB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=82c310d04b0fdd48dfece56a4186f5d0940185d8



--------------------------------

commit 0a727b45 upstream.

For example, memory-region in .dts as below,
	reg = <0x0 0x50000000 0x0 0x20000000>

We can get below values,
struct resource r;
r.start = 0x50000000;
r.end	= 0x6fffffff;

So the size should be:
size = r.end - r.start + 1 = 0x20000000

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Fixes: 072f1f91 ("drm/msm: add support for "stolen" mem")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220112123334.749776-1-xianting.tian@linux.alibaba.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>