accel/ivpu: Rename and cleanup MMU600 page tables

Simplify and unify naming convention in MMU600 page tables
configuration.

All DMA addresses in page tables directly accessed by VPU are called
with _dma sufix and all CPU pointers to those page tables have _ptr
sufix.

Base pointers used to do a page walk on the CPU have corresponding
names:

 pud_ptrs (pointers used to get access to PUD DMA)
 pmd_ptrs (pointers used to get access to PMD DMA)
 pte_ptrs (pointers used to get access to PTE DMA)

with the following convention:

 u64 *pud_dma_ptr = pud_ptrs[pgd_idx];
 *pud_dma_ptr = pud_dma;

 u64 *pmd_dma_ptr = pmd_ptrs[pgd_idx][pud_idx];
 *pmd_dma_ptr = pmd_dma;

 u64 *pte_dma_ptr = pte_ptrs[pgd_idx][pud_idx][pmd_idx];
 *pte_dma_ptr = pte_dma;

On the way change to coherent dma allocation, _wc is only valid on ARM
and was used by mistake.

Signed-off-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230518131605.650622-5-stanislaw.gruszka@linux.intel.com