msm: kgsl: Send the right IB size to adreno_find_ctxtmem

adreno_find_ctxtmem expects byte lengths and we were sending it
dword lengths which was about as effective as you would expect.

Change-Id: Ic0dedbad536ed377f6253c3a5e75e5d6cb838acf
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>