mlxfw: fix null-ptr-deref in mlxfw_mfa2_tlv_next()

Function mlxfw_mfa2_tlv_multi_get() returns NULL if 'tlv' in
question does not pass checks in mlxfw_mfa2_tlv_payload_get(). This
behaviour may lead to NULL pointer dereference in 'multi->total_len'.
Fix this issue by testing mlxfw_mfa2_tlv_multi_get()'s return value
against NULL.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 410ed13cae39 ("Add the mlxfw module for Mellanox firmware flash process")
Co-developed-by: Natalia Petrova <n.petrova@fintech.ru>
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20230417120718.52325-1-n.zhandarovich@fintech.ru
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

mlxfw: Replace license text with SPDX identifiers and adjust copyrights

Signed-off-by: Shalom Toledo <shalomt@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add the mlxfw module for Mellanox firmware flash process

The mlxfw module is in charge of common logic needed to flash Mellanox
devices firmware, which consists of:
- Parse the Mellanox Firmware Archive version 2 (MFA2) format, which is
the format used to store the Mellanox firmware. The MFA2 format file can
hold firmware for many different silicon variants, differentiated by a
unique ID called PSID. In addition, the MFA2 file data section is
compressed using xz compression to save both file-system space and
memory at extraction time.
- Implement the firmware flash state machine logic, which is a common
logic for Mellanox products needed to flash the firmware to the device.

As the module is shared between different Mellanox products, it defines a
set of callbacks to be implemented by the specific driver for hardware
interaction.

Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>