i965: Fix brw_vs_prog_data_compare to actually check field members.
i965: Fix brw_vs_prog_data_compare to actually check field members.

&a and &b are the address of the local stack variables, not the actual
structures.  Instead of comparing the fields of a and b, we compared
...some stack memory.

Caught by Valgrind on Piglit's glsl-lod-bias test (among many others).

Signed-off-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68233
Reviewed-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@linux.intel.com>
Cc: 59f39c0db42d4479a46b02d4d2bc11120e37bb44@lists.freedesktop.org

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