msm: qpnp-power-on: Update SOFT_RB_SPARE register mask

A total of six bits are allocated in the SOFT_RB_SPARE PON register
to store device restart reasons. Update the mask and shift values
used to write to this register so that a total of 64 restart reasons
can be supported using the top six bits of this register.

Change-Id: Ic4fdcb958d6aed18e7983c739bfd36decde72a5a
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>