fix: boot ROM type validation

src/gb.rs

@@ -1188,7 +1188,7 @@ impl GameBoy {
 
     pub fn load_boot_dmg(&mut self, boot_rom: Option<BootRom>) -> Result<(), Error> {
         let boot_rom = boot_rom.unwrap_or(BootRom::DmgBootix);
-        if !boot_rom.is_cgb() {
+        if !boot_rom.is_dmg_compat() {
             return Err(Error::IncompatibleBootRom);
         }
         self.load_boot_static(boot_rom);
@@ -1220,7 +1220,7 @@ impl GameBoy {
 
     pub fn load_boot_dmg_f(&mut self, boot_rom: Option<BootRom>) -> Result<(), Error> {
         let boot_rom = boot_rom.unwrap_or(BootRom::DmgBootix);
-        if !boot_rom.is_cgb() {
+        if !boot_rom.is_dmg_compat() {
             return Err(Error::IncompatibleBootRom);
         }
         self.load_boot_file(boot_rom)?;