habanalabs: Use 'dma_set_mask_and_coherent()'

Axe 'hl_pci_set_dma_mask()' and replace it with an equivalent
'dma_set_mask_and_coherent()' call.

This makes the code a bit less verbose.

It also removes an erroneous comment, because 'hl_pci_set_dma_mask()'
does not try to use a fall-back value.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>