[PATCH] Buttons in storage settings

Due to changes in layout of storage wizard base,
2 extra buttons are shown on progress screen while formatting SD card
and also on other screens which have storage wizard base as their super class.
Hence when these buttons were clicked unsupported exception takes place.
Hide these unnecessary next/back buttons from all screen so that user cannot click these.

Fixes: 131779469
Test: manual
Change-Id: I235a180627e68bbb38f4ed4e7ac58ae38838c8d7
Signed-off-by: JeiFeng Lee <linger.lee@mediatek.com>