ggml: fixed Arm SVE usage bug in vec.h, vec.cpp (#22841)
* Updated vec.h/vec.cpp code to accumulate to F32 rather than F16
Change-Id: I0cb789347f2bf60ffaf9047319f727e788c825f8
Signed-off-by: Martin Klacer <martin.klacer@arm.com>
Co-authored-by: Milos Puzovic <Milos.Puzovic@arm.com>
