svga: Fix a strict-aliasing violation in shader dumper

svga: Fix a strict-aliasing violation in shader dumper

As per the C spec, it is illegal to alias pointers to different
types. This results in undefined behaviour after optimization
passes, resulting in very subtle bugs that happen only on a
full moon..

Use a memcpy() as a well defined coercion between the isomorphic
bit-field interpretations of memory.

V.2: Use C99 compat STATIC_ASSERT() over C11 static_assert().

Signed-off-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: Charmaine Lee <charmainel@vmware.com>