wcnss: add condition to check for pronto ver3 hardware

Add support to check for pronto ver3 hardware is present
by reading a device tree entry

Change-Id: I01cd71ac6c00b6c1e4c5ea46b3f3c0b57a0dbd95
CRs-Fixed: 737209
Signed-off-by: Siddharth Bhal <sbhal@codeaurora.org>