glsl: Remove unused includes in link_uniform_init.
glsl: Remove unused includes in link_uniform_init.

Found with IWYU, confirmed with grepping for "hash" and "symbol".
No negative effects on compilation.

IWYU also reported core.h and linker.h could be removed,
but I'm unsure if those are false positives.

Reviewed-by: Tom Stellard <85590917cb30a670bf23f5b4273617f8815d1e87@amd.com>
Reviewed-by: Matt Turner <789b315743a28dd066a4ba1459c35951c291d8a6@gmail.com>
Signed-off-by: Thomas Helland <ca565e508460f734dd9d29a6ab6bd7e0e3ccde1d@gmail.com>

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