target/sparc/translate: silence the compiler warnings

target/sparc/translate: silence the compiler warnings

When using -Wimplicit-fallthrough in our CFLAGS, the compiler showed warning:
target/sparc/translate.c: In function ‘gen_st_asi’:
target/sparc/translate.c:2320:12: warning: this statement may fall through [-Wimplicit-fallthrough=]
 2320 |         if (!(dc->def->features & CPU_FEATURE_HYPV)) {
      |            ^
target/sparc/translate.c:2329:5: note: here
 2329 |     case GET_ASI_DIRECT:
      |     ^~~~

The "fall through" statement place is not correctly identified by the compiler.

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Artyom Tarasenko <atar4qemu@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20201211152426.350966-9-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>