wifi: brcmfmac: avoid assignment in if/else-if conditions in NVRAM load path

wifi: brcmfmac: avoid assignment in if/else-if conditions in NVRAM load path

The NVRAM selection logic in brcmf_fw_request_nvram_done() used
patterns like:

    if ((data = bcm47xx_nvram_get_contents(&data_len)))
        free_bcm47xx_nvram = true;
    else if ((data = brcmf_fw_nvram_from_efi(&data_len)))
        kfree_nvram = true;

This style violates kernel coding style guidelines and triggers
checkpatch.pl errors. It also slightly reduces readability.

Refactor these cases by separating the assignment and the check,
ensuring behavior remains identical while complying with coding
standards.

Signed-off-by: Darshan Rathod <darshanrathod475@gmail.com>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Link: https://patch.msgid.link/20250812123636.2142292-1-darshanrathod475@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>