dsp: fix NULL pointer exception in core driver

NULL pointer dereference occurs while getting version size
when version info memory allocation fails.
Add NULL check to avoid this NULL pointer exception.

CRs-Fixed: 2142971
Change-Id: I47a905a9b4e767d54b406a279626369f18a861d9
Signed-off-by: Aditya Bavanari <abavanar@codeaurora.org>