habanalabs: fix kernel pointer type

All throughout the driver, normal kernel pointers are
stored as 'u64' struct members, which is kind of silly
and requires casting through a uintptr_t to void* every
time they are used.

There is one line that missed the intermediate uintptr_t
case, which leads to a compiler warning:

drivers/misc/habanalabs/common/command_buffer.c: In function 'hl_cb_mmap':
drivers/misc/habanalabs/common/command_buffer.c:512:44: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
  512 |  rc = hdev->asic_funcs->cb_mmap(hdev, vma, (void *) cb->kernel_address,

Rather than adding one more cast, just fix the type and
remove all the other casts.

Fixes: 0db57535 ("habanalabs: make use of dma_mmap_coherent")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>