glsl: Fix 'format not a string literal and no format arguments' warning.
glsl: Fix 'format not a string literal and no format arguments' warning.

Fix the following GCC warning.
loop_controls.cpp: In function 'int calculate_iterations(ir_rvalue*, ir_rvalue*, ir_rvalue*, ir_expression_operation)':
loop_controls.cpp:88: warning: format not a string literal and no format arguments

zz85/glsl-optimizer,KTXSoftware/glsl2agal,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,mcanthony/glsl-optimizer,djreep81/glsl-optimizer,bkaradzic/glsl-optimizer,adobe/glsl2agal,dellis1972/glsl-optimizer,adobe/glsl2agal,adobe/glsl2agal,zz85/glsl-optimizer,KTXSoftware/glsl2agal,dellis1972/glsl-optimizer,bkaradzic/glsl-optimizer,zeux/glsl-optimizer,jbarczak/glsl-optimizer,zeux/glsl-optimizer,metora/MesaGLSLCompiler,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,bkaradzic/glsl-optimizer,dellis1972/glsl-optimizer,mapbox/glsl-optimizer,KTXSoftware/glsl2agal,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,tokyovigilante/glsl-optimizer,KTXSoftware/glsl2agal,zeux/glsl-optimizer,dellis1972/glsl-optimizer,djreep81/glsl-optimizer,metora/MesaGLSLCompiler,mcanthony/glsl-optimizer,benaadams/glsl-optimizer,mcanthony/glsl-optimizer,metora/MesaGLSLCompiler,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,benaadams/glsl-optimizer,wolf96/glsl-optimizer,djreep81/glsl-optimizer,wolf96/glsl-optimizer,wolf96/glsl-optimizer,adobe/glsl2agal,jbarczak/glsl-optimizer,dellis1972/glsl-optimizer,djreep81/glsl-optimizer,bkaradzic/glsl-optimizer,mcanthony/glsl-optimizer,mapbox/glsl-optimizer,benaadams/glsl-optimizer,benaadams/glsl-optimizer,jbarczak/glsl-optimizer,wolf96/glsl-optimizer,djreep81/glsl-optimizer,zz85/glsl-optimizer,jbarczak/glsl-optimizer,KTXSoftware/glsl2agal,mcanthony/glsl-optimizer,bkaradzic/glsl-optimizer,zeux/glsl-optimizer,benaadams/glsl-optimizer,zeux/glsl-optimizer,mapbox/glsl-optimizer,mapbox/glsl-optimizer,tokyovigilante/glsl-optimizer,adobe/glsl2agal,wolf96/glsl-optimizer