fix(riscv64): keep signed strides in RVV ROTM

The general-stride ROTM path already computes kx/ky with the BLAS negative-increment starting offset. Converting negative increments to positive strides and moving dx/dy again double-adjusted the address and could access the wrong elements. Keep the signed byte strides for RVV strided loads and stores.

Author: moluopro

kernel/riscv64/rotm_rvv.c

@@ -229,14 +229,6 @@ int CNAME(BLASLONG n, FLOAT *dx, BLASLONG incx, FLOAT *dy, BLASLONG incy, FLOAT
 L80:
     dh12 = dparam[4];
     dh21 = dparam[3];
-    if(incx < 0){
-        incx = -incx;
-        dx -= n*incx;
-    }
-    if(incy < 0){
-        incy = -incy;
-        dy -= n*incy;
-    }
     stride_x = incx * sizeof(FLOAT);
     stride_y = incy * sizeof(FLOAT);
     for (size_t vl; n > 0; n -= vl, dx += vl*incx, dy += vl*incy) {
@@ -255,14 +247,6 @@ int CNAME(BLASLONG n, FLOAT *dx, BLASLONG incx, FLOAT *dy, BLASLONG incy, FLOAT
 L100:
     dh11 = dparam[2];
     dh22 = dparam[5];
-    if(incx < 0){
-        incx = -incx;
-        dx -= n*incx;
-    }
-    if(incy < 0){
-        incy = -incy;
-        dy -= n*incy;
-    }
     stride_x = incx * sizeof(FLOAT);
     stride_y = incy * sizeof(FLOAT);
     for (size_t vl; n > 0; n -= vl, dx += vl*incx, dy += vl*incy) {
@@ -283,14 +267,6 @@ int CNAME(BLASLONG n, FLOAT *dx, BLASLONG incx, FLOAT *dy, BLASLONG incy, FLOAT
     dh12 = dparam[4];
     dh21 = dparam[3];
     dh22 = dparam[5];
-    if(incx < 0){
-        incx = -incx;
-        dx -= n*incx;
-    }
-    if(incy < 0){
-        incy = -incy;
-        dy -= n*incy;
-    }
     stride_x = incx * sizeof(FLOAT);
     stride_y = incy * sizeof(FLOAT);
     for (size_t vl; n > 0; n -= vl, dx += vl*incx, dy += vl*incy) {