Fixed some quad layout computation related warnings
Fixed some quad layout computation related warnings

Linux was complaining about ambiguous conditional expressions.
Added some explicit casts to RValue<Int> to fix these warnings.

Change-Id: Ib8e01ee69bb1794ea60b7954f1520a15e383cefa
Reviewed-on: https://swiftshader-review.googlesource.com/8111
Tested-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Reviewed-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>

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