drm/i915/guc: Use GuC submission API version number

The GuC firmware includes an extra version number to specify the
submission API level. So use that rather than the main firmware
version number for submission related checks.

Also, while it is guaranteed that GuC version number components are
only 8-bits in size, other firmwares do not have that restriction. So
stop making assumptions about them generically fitting in a u16
individually, or in a u32 as a combined 8.8.8.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221129232031.3401386-4-John.C.Harrison@Intel.com