st/vega: fix uninitialized values

st/vega: fix uninitialized values

C still treats array arguments exactly like pointer arguments.
By sheer coincidence, this still worked fine on 64-bit
machines where 2 * sizeof(float) == sizeof(void*), but not
on 32-bit.

Noticed by clang:

text.c:76:51: warning: sizeof on array function parameter will
return size of 'const VGfloat *' (aka 'const float *') instead of
'const VGfloat [2]' [-Wsizeof-array-argument]
   memcpy(glyph->glyph_origin, glyphOrigin, sizeof(glyphOrigin));

NOTE: This is a candidate for the 8.0 branch.

Reviewed-by: Brian Paul <brianp@vmware.com>