cnss2: Avoid shadow register dump in RDDM mode
Before CNSS2 triggers RDDM mode in device it collects shadow
register dump in a global variable. Now when device moves to
RDDM, shadow registers will be reset. Reading shadow registers
in RDDM mode will override previously read correct values with
reset values. To avoid it, do not dump shadow register in RDDM
mode.
Change-Id: I470208be7e38bc9291932a7acfbaf07d87d46651