uboot-phytec

stm32mp1: ram: fix address issue in 2 tests

If user choose to test memory size is 1GByte (0x40000000),
memory address would overflow in test "Random" and
test "FrequencySelectivePattern".
Thus the system would hangs up when running DDR test.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Bossen WU <bossen.wu@st.com>