lib test: only erase once for in step test

Signed-off-by: Wang Xingchao <xingchao.wang@linux.intel.com>
u1sram test: change test count

Signed-off-by: Wang Xingchao <xingchao.wang@linux.intel.com>
u1sram test: Add loop number for test

Signed-off-by: Wang Xingchao <xingchao.wang@linux.intel.com>