soc: cpu_pwr_ctl: modify the CPU and L2 sequence for 8994-V2

The CPU and L2 bootup sequence has different timing restrictions for
8994 V2. Modify the sequence as per the recommendations. This should
continue to work for 8994 V1.

Change-Id: Ia31e26f9e616713dc0671792407173e92c5ab44a
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>