msm: kgsl: Detach context when context creation fails in create function

If context creation fails in the creation function then we need to detach
the context and destroy it and not just destroy it to properly clean
up the resources allocated for the context.

Change-Id: I686b2f3090deae2fc9211acce12234daf063d913
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>