Fix operator precedence issue.
Fix operator precedence issue.

Addition evaluates before the ternary operator, which resulted in the wrong
sizes being computed.

Bug 28346104

Change-Id: Id28843132097a4fb1599eed19c05f479f16f1315
Reviewed-on: https://swiftshader-review.googlesource.com/5187
Reviewed-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Reviewed-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>
Tested-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>

bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader