Claude review: drm: Suppress intentional warning backtraces in scaling unit tests

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**Clean practical demonstration.** The changes wrap `drm_rect_calc_hscale()` and `drm_rect_calc_vscale()` calls in `kunit_warning_suppress()` blocks:

```c
int expected_warnings = params->expected_scaling_factor == -EINVAL;
int scaling_factor = INT_MIN;

kunit_warning_suppress(test) {
	scaling_factor = drm_rect_calc_hscale(&params->src, &params->dst,
					      params->min_range,
					      params->max_range);
	KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT(test, expected_warnings);
}
```

The `expected_warnings` calculation (`== -EINVAL` yields 0 or 1) correctly maps the error cases to expected warning counts. Initializing `scaling_factor = INT_MIN` ensures a clearly wrong value if the suppression block is somehow skipped (e.g., allocation failure causes `kunit_start_suppress_warning()` to return NULL → loop body never executes). In that case the subsequent `KUNIT_EXPECT_EQ(test, scaling_factor, ...)` would fail, which is the right behavior.

The `#include <linux/limits.h>` for `INT_MIN` is correct.

**Note:** The suppression wraps *all* parameterized test iterations, not just the `-EINVAL` ones. For non-error cases, `expected_warnings` is 0, so the `KUNIT_EXPECT_SUPPRESSED_WARNING_COUNT` check verifies no spurious warnings. This is a nice property.

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