RDMA/mana_ib: Allocate PAGE aligned doorbell index

Allocate a PAGE aligned doorbell index to ensure each process gets a
separate PAGE sized doorbell area space remapped to it in mana_ib_mmap

Fixes: 0266a177 ("RDMA/mana_ib: Add a driver for Microsoft Azure Network Adapter")
Signed-off-by: Shiraz Saleem <shirazsaleem@microsoft.com>
Signed-off-by: Konstantin Taranov <kotaranov@microsoft.com>
Link: https://patch.msgid.link/1738751405-15041-1-git-send-email-kotaranov@linux.microsoft.com


Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>