kfdtest: make p2ptest go through all gpus

Implement sDMA copy packet broadcast.

Each time sDMA will copy its local vram to sysbuf and next GPU's vram.
That will verify where the p2p link is broken.
Currently we just test push of p2p.

test result on 2 cpus, 4 gpus, numa enabled system.
[ RUN      ] KFDQMTest.P2PTest
[          ] Test 2 -> 3
[          ] PASS 2 -> 3
[          ] Test 3 -> 4
[          ] PASS 3 -> 4
[          ] Test 4 -> 5
[          ] PASS 4 -> 5
[          ] Test 5 -> 0
[          ] PASS 5 -> 0
[       OK ] KFDQMTest.P2PTest (190 ms)

Change-Id: Ie6fb2604109e39465b8a873b3bb42abc6259825a

tests/kfdtest/include/sdma_pkt_struct.h

@@ -102,23 +102,26 @@ typedef struct SDMA_PKT_COPY_LINEAR_TAG
         unsigned int DW_4_DATA;
     } SRC_ADDR_HI_UNION;
 
-    union
+    struct
     {
-        struct
+        union
         {
-            unsigned int dst_addr_31_0:32;
-        };
-        unsigned int DW_5_DATA;
-    } DST_ADDR_LO_UNION;
+            struct
+            {
+                unsigned int dst_addr_31_0:32;
+            };
+            unsigned int DW_5_DATA;
+        } DST_ADDR_LO_UNION;
 
-    union
-    {
-        struct
+        union
         {
-            unsigned int dst_addr_63_32:32;
-        };
-        unsigned int DW_6_DATA;
-    } DST_ADDR_HI_UNION;
+            struct
+            {
+                unsigned int dst_addr_63_32:32;
+            };
+            unsigned int DW_6_DATA;
+        } DST_ADDR_HI_UNION;
+    } DST_ADDR[0];
 } SDMA_PKT_COPY_LINEAR, *PSDMA_PKT_COPY_LINEAR;
 
 /*