Get rid of most instance of 'foo == NULL'

core/src/fdrm/crypto/fx_crypt_sha.cpp

Index: core/src/fdrm/crypto/fx_crypt_sha.cpp
diff --git a/core/src/fdrm/crypto/fx_crypt_sha.cpp b/core/src/fdrm/crypto/fx_crypt_sha.cpp
index ecefdde05a8675aff0cf67f29927ce4626bd58ff..c7d171098bd3e38a5aa9b274928d481d3d2af708 100644
--- a/core/src/fdrm/crypto/fx_crypt_sha.cpp
+++ b/core/src/fdrm/crypto/fx_crypt_sha.cpp
@@ -390,7 +390,7 @@ uint64_t FX_ato64i(const FX_CHAR* str) {
   return ret;
 }
 void CRYPT_SHA384Start(void* context) {
-  if (context == NULL) {
+  if (!context) {
     return;
   }
   sha384_context* ctx = (sha384_context*)context;
@@ -604,7 +604,7 @@ void CRYPT_SHA384Generate(const uint8_t* data,
   CRYPT_SHA384Finish(&context, digest);
 }
 void CRYPT_SHA512Start(void* context) {
-  if (context == NULL) {
+  if (!context) {
     return;
   }
   sha384_context* ctx = (sha384_context*)context;