Kernel/Storage: Convert StorageDevice class members to be const

It is expected that these class members will be set when the object is
created (so they're set in the class constructor method) and never
change again, as its the driver responsibility to find these values
before creating a StorageDevice object.

This makes it easier to rely on these values later on as we don't expect
them to ever change for a StorageDevice object during its lifetime.

Kernel/Devices/Storage/StorageDevice.h

@@ -109,8 +109,8 @@ private:
     // controller among its fellow controllers of the same hardware type in the system.
     u32 const m_hardware_relative_controller_id { 0 };
 
-    u64 m_max_addressable_block { 0 };
-    size_t m_blocks_per_page { 0 };
+    u64 const m_max_addressable_block { 0 };
+    size_t const m_blocks_per_page { 0 };
 };
 
 }