fixed sRGB-texture related compile erros for gles 2.0
fixed sRGB-texture related compile erros for gles 2.0

attilaz/bgfx,LWJGL-CI/bgfx,0-wiz-0/bgfx,jpcy/bgfx,cyndis/bgfx,bkaradzic/bgfx,mcanthony/bgfx,mmicko/bgfx,Synxis/bgfx,andr3wmac/bgfx,attilaz/bgfx,janstk/bgfx,Extrawurst/bgfx,Synxis/bgfx,BlueCrystalLabs/bgfx,mendsley/bgfx,marco-we/bgfx,kondrak/bgfx,darkimage/bgfx,jdryg/bgfx,attilaz/bgfx,ocornut/bgfx,jdryg/bgfx,bkaradzic/bgfx,fluffyfreak/bgfx,jpcy/bgfx,marco-we/bgfx,mmicko/bgfx,0-wiz-0/bgfx,cuavas/bgfx,v3n/bgfx,BlueCrystalLabs/bgfx,septag/bgfx,marco-we/bgfx,aonorin/bgfx,Vertexwahn/bgfx,elmindreda/bgfx,janstk/bgfx,bkaradzic/bgfx,mendsley/bgfx,cyndis/bgfx,cuavas/bgfx,v3n/bgfx,darkimage/bgfx,cuavas/bgfx,LWJGL-CI/bgfx,LSBOSS/bgfx,MikePopoloski/bgfx,janstk/bgfx,0-wiz-0/bgfx,BlueCrystalLabs/bgfx,bkaradzic/bgfx,mcanthony/bgfx,andr3wmac/bgfx,emoon/bgfx,jdryg/bgfx,ktotheoz/bgfx,emoon/bgfx,Vertexwahn/bgfx,ktotheoz/bgfx,Extrawurst/bgfx,v3n/bgfx,MikePopoloski/bgfx,fluffyfreak/bgfx,darkimage/bgfx,Extrawurst/bgfx,ktotheoz/bgfx,cyndis/bgfx,LWJGL-CI/bgfx,LSBOSS/bgfx,ocornut/bgfx,mcanthony/bgfx,sergeScherbakov/bgfx,mendsley/bgfx,jpcy/bgfx,kondrak/bgfx,fluffyfreak/bgfx,mmicko/bgfx,septag/bgfx,septag/bgfx,elmindreda/bgfx,jdryg/bgfx,Synxis/bgfx,aonorin/bgfx,Vertexwahn/bgfx,aonorin/bgfx,andr3wmac/bgfx,kondrak/bgfx,ocornut/bgfx,MikePopoloski/bgfx,sergeScherbakov/bgfx,emoon/bgfx,sergeScherbakov/bgfx,LSBOSS/bgfx,elmindreda/bgfx,fluffyfreak/bgfx,jpcy/bgfx,LWJGL-CI/bgfx