Support using 7 bits in the SOFT_RB_SPARE PON register if the
PON peripheral is GEN2, otherwise use only 6 bits. This allows
compatibility with bootloader code on targets with older PMICs
where 7 bits for restart reasons are not necessary.
Change-Id: Ibf7fc53d3ff7084b252a44c44e3ce29326659787
CRs-Fixed: 1023239
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>