media: intel/ipu6: Don't re-allocate memory for firmware

The ipu6 driver allocated vmalloc memory for the firmware if
request_firmware() somehow managed not to use vmalloc to allocate it.

Still how the memory is allocated by request_firmware() is not specified
in its API, so be prepared for kmalloc-allocated firmware, too. Instead of
allocating new vmalloc-backed buffer for the firmware, obtain the pages
from virtual addresses instead.

Link: https://lore.kernel.org/linux-media/20240502154950.549015-1-sakari.ailus@linux.intel.com


Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/all/20240501102236.3b2585d1@canb.auug.org.au/


Fixes: 25fedc02 ("media: intel/ipu6: add Intel IPU6 PCI device driver")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>