i965: Bump official kernel requirement to Linux v3.9.

i965: Bump official kernel requirement to Linux v3.9.

In commit 3f353342a6b6744773c26ed66b12afed42bd57af (present in 17.3.0)
we started unconditionally using I915_EXEC_NO_RELOC, which was
introduced in Linux v3.9.  ChromeOS kernel 3.8 has backported this,
so it should work too.

Running on older kernels would likely result in every single batch
being rejected by the kernel, which is pretty catastrophic.  Yet, it
appears that nobody noticed.  So, let's just bump the official
requirement and move forward ever so slowly.

Fixes: 3f353342a6b ("i965: Use I915_EXEC_NO_RELOC")
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Emil Velikov <emil.velikov@collabora.com>