gpu: vivante: Removed functions that only call an "Ex" variant

The "Ex" functions take an extra gceCORE argument, to which the non-Ex
function passes gcvCORE_MAJOR.

Note that there are still some functions left with both an Ex and a
non-Ex variant, but for those the added argument is not a gceCORE.
gpu: vivante: Made 8 functions from gc_hal_kernel_device.c static

Most of the diff is from moving the functions to a place in the source
prior to their first use.
gpu: vivante: Removed functions which have no callers
gpu: vivante: Made functions used only in one source file static