bnxt_en: Add bnxt_hwrm_nvm_get_dev_info() to query NVM info.

Add a new bnxt_hwrm_nvm_get_dev_info() to query firmware version
information via NVM_GET_DEV_INFO firmware command.  Use it to
get the running version of the NVM configuration information.

This new function will also be used in subsequent patches to get the
stored firmware versions.

Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/1602493854-29283-8-git-send-email-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>