mtd: msm_qpic_nand: Add boot_a and boot_b access to APPS

The existing code logic, checks for partitions that have
access to apps by name "boot". This logic may not work
if the boot partition name changes, let's say as boot_a/b.

So, get the active boot partition details by reading the
new kernel command line parameter "part.activeboot=" and
use this partition page offset address to read the ONFI
parameter page. If active boot partition details are
not found, fallback to legacy code.

Change-Id: I7c7071ccfc687f2e03bd9209a3c7260fb131ff10
Signed-off-by: Pradeep P V K <quic_pragalla@quicinc.com>