cuda : fix bounds check for src0 rows in MMVQ kernel (whisper/2231)

* cuda : fix bounds check for src0 rows in MMVQ kernel

* Update ggml-cuda/mmvq.cu

Co-authored-by: Johannes Gäßler <johannesg@5d6.de>

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Co-authored-by: Johannes Gäßler <johannesg@5d6.de>