pygpu: Don't change addres space when casting pointer.

Fixes pygpu.tests.test_basic.test_triu and
pygpu.tests.test_basic.test_tril on amdgpu/clover

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

pygpu/basic.py

@@ -6,7 +6,7 @@ def _generate_kernel(ctx, cols, upper=True):
     tmpl = Template("""
     #include "cluda.h"
     KERNEL void extract_tri(GLOBAL_MEM ga_float *a, ga_size a_off, ga_uint N) {
-        a = (GLOBAL_MEM ga_float *)(((char *)a) + a_off);
+        a = (GLOBAL_MEM ga_float *)(((GLOBAL_MEM char *)a) + a_off);
         unsigned int idx = GID_1 * LDIM_0 * GDIM_0 +
                            GID_0 * LDIM_0 + LID_0;
         unsigned int ix = idx/${cols};