gpu: vivante: Removed COMMAND_PROCESSOR_VERSION option

If this option was not set to 1 (the default), the code would try to
use the unimplemented function gckINTERRUPT_Notify on the non-existant
"interrupt" field in struct _gckKERNEL.
gpu: vivante: Removed gcdSMP option

The gcdSMP option matched CONFIG_SMP. This commit changes the code to
inspect CONFIG_SMP directly instead.
gpu: vivante: Replace gcmCOUNTOF macro by ARRAY_SIZE
gpu: vivante: Replace gcvNULL macro by NULL