msm: kgsl: Use init_utsname() instead of ustname() for kernel build info.

Using per uts namespace utsname() for kernel build information section
in snapshot dump was causing a kernel panic because it is accessing a
NULL nsproxy pointer. nsproxy was null because corresponding user task
got SIGKILL which triggered call to free_nsproxy. The patch fixes the
issue by using the global init_utsname() which is always valid.

Change-Id: I13b1b07557794a7fcedf0c9e6acfd3406fbb8989
Signed-off-by: Deepak Kumar <dkumar@codeaurora.org>