memory: brcmstb: dpfe: move init_data into brcmstb_dpfe_download_firmware()

Rather than declaring our init_data in several places and passing it as
parameter into brcmstb_dpfe_download_firmware(), we declare it inside
brcmstb_dpfe_download_firmware() instead.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>