msm: kgsl: Check for failure in coresight initialization

We need to check for both NULL pointer and error condition
in coresight initialization and return with proper error.

CR's-Fixed: 971398
Change-Id: Id1e3e0f756ac1c9a0ff4f4e6ce073e80e31473b8
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>