dynamically generate strides in fmap_find() to cover all of ROM

This changes the hard coded array of strides to cover with an algorithm that
will result in every bit of the ROM being checked.  Now the algorithm starts
at 1/2 the ROM's total size and divides its stride by 2 on each iteration.

TEST=Tested on Alex with an FMAP structure at various alignments (2M, 1M, 64K, 4K, 16, 5, 1).

Review URL: http://codereview.chromium.org/6612048
1 file changed