sf: Use read|erase|write_addr instead of offset

Used read|erase|write_addr instead of offset in respective
flash read/erase/write operations to make sure that all
qspi modes are sync with the updated sf framework.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>