drm/i915: Fix -Wstringop-overflow warning in call to intel_read_wm_latency()

stable inclusion
from stable-v5.10.120
commit 1f0681f3bd5665080bde3c5b9568cc27df765ce0
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6BR

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1f0681f3bd5665080bde3c5b9568cc27df765ce0

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

commit 336feb50 upstream.

Fix the following -Wstringop-overflow warnings when building with GCC-11:

drivers/gpu/drm/i915/intel_pm.c:3106:9: warning: ‘intel_read_wm_latency’ accessing 16 bytes in a region of size 10 [-Wstringop-overflow=]
 3106 |         intel_read_wm_latency(dev_priv, dev_priv->wm.pri_latency);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/intel_pm.c:3106:9: note: referencing argument 2 of type ‘u16 *’ {aka ‘short unsigned int *’}
drivers/gpu/drm/i915/intel_pm.c:2861:13: note: in a call to function ‘intel_read_wm_latency’
 2861 | static void intel_read_wm_latency(struct drm_i915_private *dev_priv,
      |             ^~~~~~~~~~~~~~~~~~~~~

by removing the over-specified array size from the argument declarations.

It seems that this code is actually safe because the size of the
array depends on the hardware generation, and the function checks
for that.

Notice that wm can be an array of 5 elements:
drivers/gpu/drm/i915/intel_pm.c:3109:   intel_read_wm_latency(dev_priv, dev_priv->wm.pri_latency);

or an array of 8 elements:
drivers/gpu/drm/i915/intel_pm.c:3131:   intel_read_wm_latency(dev_priv, dev_priv->wm.skl_latency);

and the compiler legitimately complains about that.

This helps with the ongoing efforts to globally enable
-Wstringop-overflow.

Link: https://github.com/KSPP/linux/issues/181


Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>