sf: spansion: Correct name of S25FL128S 64K Sector part

Corrected the name of S25FL128S 64K sector part SPI flash,
S25FL128S supported has been added in below commit
"sf: spansion: Add support for S25FL128S"
(sha1: 1bfb9f15)

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>