msm: kgsl: Don't spam kmsg due to invalid IOCTL requests

When the IOCTL is called with invalid data, don't log to kmsg. The
returned error code should be enough to tell the UMD what they did wrong.

CRs-Fixed: 987074
Change-Id: Iae380e0f44dd53bee8ff4cec347a6b9a632b1f84
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>