kfdtest : adjust memory size for KFDMemoryTest.

Total VRAM size on APU is 512M usually,
Framebuffer also is allocated from VRAM.
There is no enough memory for this case.

/home/ruiliji2/p5/libhsakmt/tests/kfdtest/src/KFDMemoryTest.cpp:1285: Failure
Value of: (hsaKmtMapMemoryToGPUNodes(bufs[i], bufSize, &altVa, mapFlags, 1, &defaultGPUNode))
[  FAILED  ] KFDMemoryTest.MMBench (1034 ms)

Change-Id: Ib4201291122d85f6512a85859aea9a4713fb4f5c
(cherry picked from commit a9f924484e7022a2d53ee02811b080f0833eba55)


[ROCm/ROCR-Runtime commit: 0340c68031]

projects/rocr-runtime/tests/kfdtest/src/KFDMemoryTest.cpp

@@ -1255,7 +1255,8 @@ TEST_F(KFDMemoryTest, MMBench) {
             memFlags.ui32.HostAccess = 0;
             memFlags.ui32.NonPaged = 1;
             /* Upper limit of buffer number to fit 90% vram size */
-            bufLimit = ((vramSizeMB << 20) * 9 / 10) / bufSize ;
+            bufLimit = ((vramSizeMB << 20) * 8 / 10) / bufSize ;
+
             if (bufLimit == 0)
                 continue; // skip when bufSize > vram