Fix compilation error on android build.

The error that appears when trying to build swiftshader master as part
of android is:
external/swiftshader/src/Shader/Shader.cpp:1886:51: error: expected '(' for function-style cast or type construction

Change-Id: I667f249e46ed99c3c598490182e495c0862c64a9
Reviewed-on: https://swiftshader-review.googlesource.com/c/23768
Tested-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Lingfeng Yang <lfy@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Shader/Shader.cpp b/src/Shader/Shader.cpp
index 0e06703..db2b2bc 100644
--- a/src/Shader/Shader.cpp
+++ b/src/Shader/Shader.cpp
@@ -1883,7 +1883,7 @@
 		{
 			if(inst->opcode == OPCODE_CALL || inst->opcode == OPCODE_CALLNZ)
 			{
-				int label = sw::min(inst->dst.label, unsigned int(MAX_SHADER_CALL_SITES));
+				int label = sw::min(inst->dst.label, static_cast<unsigned int>(MAX_SHADER_CALL_SITES));
 
 				inst->dst.callSite = callSiteIndex[label]++;
 			}