src/flash/nand: Fix some operator precedence bugs.

src/flash/nand: Fix some operator precedence bugs.

Fix two expressions where precedence of operator | vs ?: was clearly confused.
Untested - was clearly not expressing the intent of the author by inspection.
Found by automated tooling and rtrieu@google.com.

Change-Id: I46f190154797f8affc761caf3a15a1a9db53d702
Signed-off-by: Seth LaForge <sethml@google.com>
Reviewed-on: http://openocd.zylin.com/5281
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>