hw/m68k: Fix typo in SPDX tag

hw/m68k: Fix typo in SPDX tag

Fix 'Identifer' -> 'Identifier' typo.

Cc: Laurent Vivier <laurent@vivier.eu>
Fixes: 8c6df16ff60 ("hw/char: add goldfish-tty")
Fixes: 87855593903 ("hw/intc: add goldfish-pic")
Fixes: 2fde99ee312 ("m68k: add an interrupt controller")
Fixes: 0791bc02b8f ("m68k: add a system controller")
Fixes: e1cecdca559 ("m68k: add Virtual M68k Machine")
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20211103105311.3399293-1-f4bug@amsat.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>