qed: Optimize execution time for nvm attributes configuration.

Current implementation for nvm_attr configuration instructs the management
FW to load/unload the nvm-cfg image for each user-provided attribute in
the input file. This consumes lot of cycles even for few tens of
attributes.
This patch updates the implementation to perform load/commit of the config
for every 50 attributes. After loading the nvm-image, MFW expects that
config should be committed in a predefined timer value (5 sec), hence it's
not possible to write large number of attributes in a single load/commit
window. Hence performing the commits in chunks.

Fixes: 0dabbe1b

 ("qed: Add driver API for flashing the config attributes.")
Signed-off-by: Sudarsana Reddy Kalluru <skalluru@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>