mem_sse2.h: storeu_uint32 -> storeu_int32

this changes the parameter to int32_t which matches the type with usage
of this call using _mm_cvtsi128_si32() as a parameter. quiets an
implicit conversion warning with clang-11 -fsanitize=undefined

Change-Id: I1e9e9ffac5d2996962d29611458311221eca8ea0
3 files changed