CommonFuncs: Convert ROUND_UP_POW2 macro to a function

Also move it to MathUtils where it belongs with the rest of the
power-of-two functions. This gets rid of pollution of the current scope
of any translation unit with b<value> macros that aren't intended to be
used directly.

Source/Core/Common/CommonFuncs.h

@@ -15,13 +15,6 @@ constexpr size_t ArraySize(T (&arr)[N])
   return N;
 }
 
-#define b2(x) ((x) | ((x) >> 1))
-#define b4(x) (b2(x) | (b2(x) >> 2))
-#define b8(x) (b4(x) | (b4(x) >> 4))
-#define b16(x) (b8(x) | (b8(x) >> 8))
-#define b32(x) (b16(x) | (b16(x) >> 16))
-#define ROUND_UP_POW2(x) (b32(x - 1) + 1)
-
 #ifndef _WIN32
 
 // go to debugger mode

Source/Core/Common/MathUtil.h

@@ -29,6 +29,19 @@ constexpr bool IsPow2(T imm)
   return imm > 0 && (imm & (imm - 1)) == 0;
 }
 
+constexpr u32 NextPowerOf2(u32 value)
+{
+  --value;
+  value |= value >> 1;
+  value |= value >> 2;
+  value |= value >> 4;
+  value |= value >> 8;
+  value |= value >> 16;
+  ++value;
+
+  return value;
+}
+
 template <class T>
 struct Rectangle
 {