habanalabs: add user API to get valid DRAM page sizes

Future devices will support multiple device memory page sizes.
In addition, an API for the user was added for it to be able to control
the device memory allocation page size.

This patch is a complementary patch to inform the user of the available
page size supported by the device.

Signed-off-by: Ohad Sharabi <osharabi@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>