spmi: pmic-arb: Dump values of dbg regs on transfer err

Dump values of core HW debugging registers on an error
in transfer. These values are valuable for root cause
analysis.

Change-Id: I206c4a2232f44480220e795a8d8e946d8352ba19
Signed-off-by: Gilad Avidov <gavidov@codeaurora.org>