remove dup -mattr

Author: Mel-Chen

llvm/test/Transforms/LoopVectorize/RISCV/interleaved-store-with-gap.ll

@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 5
-; RUN: opt -mtriple=riscv64 -mattr=+v -passes=loop-vectorize -mattr=+v \
+; RUN: opt -mtriple=riscv64 -mattr=+v -passes=loop-vectorize \
 ; RUN: -scalable-vectorization=off -enable-masked-interleaved-mem-accesses \
 ; RUN: -force-vector-interleave=1 -riscv-v-vector-bits-min=1024 -S < %s | FileCheck %s