refactor more clippy

src/cpu.rs

@@ -381,8 +381,8 @@ impl Cpu {
     pub fn read_u16(&mut self) -> u16 {
         let byte1 = self.read_u8();
         let byte2 = self.read_u8();
-        let word = byte1 as u16 | ((byte2 as u16) << 8);
-        word
+        
+        byte1 as u16 | ((byte2 as u16) << 8)
     }
 
     #[inline(always)]
@@ -406,8 +406,8 @@ impl Cpu {
 
     #[inline(always)]
     pub fn pop_word(&mut self) -> u16 {
-        let word = self.pop_byte() as u16 | ((self.pop_byte() as u16) << 8);
-        word
+        
+        self.pop_byte() as u16 | ((self.pop_byte() as u16) << 8)
     }
 
     #[inline(always)]