fix(esp_hal/adc_ll): missing-field-initializers (IDFGH-17806)

[safocl]

Description

The first member of the union is a structure with multiple data elements, but only the first member is initialized using the {0} initializer.
However, this is not required since only uint8_t is used here.

This gave the error "missing-field-initializers".

 esp-idf/components/esp_hal_ana_conv/esp32/include/hal/adc_ll.h:253:45: error: missing initializer for member 'adc_ll_digi_pattern_table_t::<unnamed union>::<unnamed struct>::bit_width' [-Werror=missing-field-initializers]
   253 |     adc_ll_digi_pattern_table_t pattern = {0};
       |                                             ^
 

Related

Testing

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Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.

[songruo]

sha=09d14e36db26bb29f68cc227e1f53a589877f7dd