drm/i915/guc: Drop union guc_log_control

drm/i915/guc: Drop union guc_log_control

Usually we use shift/mask macros for bit field definitions.
Union guc_log_control was not following that pattern.

Additional bonus:

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-25 (-25)
Function                                     old     new   delta
intel_guc_log_level_set                      388     363     -25

v2: prevent out-of-range verbosity (MichalWi)

Signed-off-by: Michal Wajdeczko <[email protected]>
Cc: Michal Winiarski <[email protected]>
Cc: Sagar Arun Kamble <[email protected]>
Reviewed-by: MichaĹ Winiarski <[email protected]>
Signed-off-by: Chris Wilson <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]