bnxt_en: Return -EROFS to user space, if NVM writes are not permitted.

bnxt_en: Return -EROFS to user space, if NVM writes are not permitted.

If NVRAM resources are locked, NVM writes are not permitted. In such
scenarios, firmware returns HWRM_ERR_CODE_RESOURCE_LOCKED error to
firmware commands.

Reviewed-by: Edwin Peer <edwin.peer@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/1602493854-29283-2-git-send-email-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>