clang-tidy: Enable readability-simplify-boolean-expr check

This check looks for boolean expressions involving boolean
constants and simplifies them to use the appropriate boolean
expression directly.

Change-Id: I79d7e4486bd0ea5f5b9b5a1644af99384e41e251
Signed-off-by: Pavithra Barithaya <pavithrabarithaya07@gmail.com>
diff --git a/image_verify.cpp b/image_verify.cpp
index 4d874b4..12e938e 100644
--- a/image_verify.cpp
+++ b/image_verify.cpp
@@ -147,7 +147,7 @@
         bool valid;
         // Verify the MANIFEST and publickey file using available
         // public keys and hash on the system.
-        if (false == systemLevelVerify())
+        if (!systemLevelVerify())
         {
             error("System level Signature Validation failed");
             return false;
@@ -211,7 +211,7 @@
             }
         }
 
-        if (verifyFullImage() == false)
+        if (!verifyFullImage())
         {
             error("Image full file Signature Validation failed");
             return false;
@@ -436,7 +436,7 @@
 
         // Verify the signature.
         valid = verifyFile(file, sigFile, publicKeyPath, hashType);
-        if (valid == false)
+        if (!valid)
         {
             error("Image file Signature Validation failed on {PATH}", "PATH",
                   bmcImage);