drivers: firmware: octeontx2: Add additional length variable

commit b019ef035d04a732a8589ab8df8bb7c1cbd7cf6f from
git@git.assembla.com:cavium/WindRiver.linux.git

This change adds an additional length variable, this is done so that
length can be configured separately based on reboot/poweron

Signed-off-by: Piyush Malgujar <pmalgujar@marvell.com>
Change-Id: I0019218841ab492ee6a9af1f6f3e1b6efc47b83a
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/92124
Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>
Reviewed-by: Felix Manlunas <fmanlunas@marvell.com>
Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/120334
Reviewed-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>