drm/prime: Fix documentation of drm_gem_prime_fd_to_handle()

The DRM device passed to drm_gem_prime_fd_to_handle() is where the
dma-buf is being imported, not the device where it was exported.

Also fix a trivial typo in drm_gem_prime_import_dev().

Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patchwork.freedesktop.org/patch/msgid/20230224120931.1024-1-petrtesarik@huaweicloud.com