siimage: PIO1/2 taskfile transfer overclocking fix

Fix two typos found by SiI680A documentation check.  They caused the taskfile
transfer overclocking:

- in PIO mode 1 as 0x2283 must be used for both data and taskfile transfers;

- in PIO mode 2 as data and taskfile timings are swapped when writing to the
  MMIO regs.

Fix coding style and trailing whitespace in enclosing statements while at it...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>