sf: Correct typo mistake on bank_boun in dual parallel

bank_boun in dual parallel should be 32Mb, Corrected the typo
mistake by using left shift << instead of right shift >> to 16Mb value.

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