fix warning on visual C for mips cpu detect

follow up warning fixs
cpu_id.cc(167): warning C4267: 'initializing': conversion from 'size_t' to 'int', possible loss of data
lint warning: cpu_id.cc:171:  Missing space before ( in if(  [whitespace/parens] [5]

TBR=manojkumar.bhosale@imgtec.com
BUG=libyuv:634
TEST=try bots for windows.

Review URL: https://codereview.chromium.org/2365813002 .

libyuv.gyp

@@ -25,6 +25,7 @@
     'clang%': 0,
     # Link-Time Optimizations.
     'use_lto%': 0,
+    'mips_msa%': 0,  # Default to msa off.
     'build_neon': 0,
     'build_msa': 0,
     'conditions': [

libyuv_test.gyp

@@ -9,6 +9,7 @@
 {
   'variables': {
     'libyuv_disable_jpeg%': 0,
+    'mips_msa%': 0,  # Default to msa off.
   },
   'targets': [
     {

source/cpu_id.cc

@@ -164,14 +164,14 @@ int ArmCpuCaps(const char* cpuinfo_name) {
 LIBYUV_API SAFEBUFFERS
 int MipsCpuCaps(const char* cpuinfo_name, const char ase[]) {
   char cpuinfo_line[512];
-  int len = strlen(ase);
+  int len = (int)strlen(ase);
   FILE* f = fopen(cpuinfo_name, "r");
   if (!f) {
     // ase enabled if /proc/cpuinfo is unavailable.
-    if(strcmp(ase, " msa") == 0) {
+    if (strcmp(ase, " msa") == 0) {
       return kCpuHasMSA;
     }
-    if(strcmp(ase, " dspr2") == 0) {
+    if (strcmp(ase, " dspr2") == 0) {
       return kCpuHasDSPR2;
     }
   }
@@ -180,10 +180,10 @@ int MipsCpuCaps(const char* cpuinfo_name, const char ase[]) {
       char* p = strstr(cpuinfo_line, ase);
       if (p && (p[len] == ' ' || p[len] == '\n')) {
         fclose(f);
-        if(strcmp(ase, " msa") == 0) {
+        if (strcmp(ase, " msa") == 0) {
           return kCpuHasMSA;
         }
-        if(strcmp(ase, " dspr2") == 0) {
+        if (strcmp(ase, " dspr2") == 0) {
           return kCpuHasDSPR2;
         }
       }