linux-user/syscall.c: clean up local variable shadowing in xattr syscalls

linux-user/syscall.c: clean up local variable shadowing in xattr syscalls

p is a generic variable in syscall() and can be used by any syscall
case, so this patch removes the useless local variable declaration for
the following syscalls: TARGET_NR_llistxattr, TARGET_NR_listxattr,
TARGET_NR_setxattr, TARGET_NR_lsetxattr, TARGET_NR_getxattr,
TARGET_NR_lgetxattr, TARGET_NR_removexattr, TARGET_NR_lremovexattr.

Fix following warnings:

.../linux-user/syscall.c:12342:15: warning: declaration of 'p' shadows a previous local [-Wshadow=compatible-local]
12342 |         void *p, *b = 0;
      |               ^
.../linux-user/syscall.c:8975:11: note: shadowed declaration is here
 8975 |     void *p;
      |           ^
.../linux-user/syscall.c:12379:19: warning: declaration of 'p' shadows a previous local [-Wshadow=compatible-local]
12379 |             void *p, *n, *v = 0;
      |                   ^
.../linux-user/syscall.c:8975:11: note: shadowed declaration is here
 8975 |     void *p;
      |           ^
.../linux-user/syscall.c:12424:19: warning: declaration of 'p' shadows a previous local [-Wshadow=compatible-local]
12424 |             void *p, *n, *v = 0;
      |                   ^
.../linux-user/syscall.c:8975:11: note: shadowed declaration is here
 8975 |     void *p;
      |           ^
.../linux-user/syscall.c:12469:19: warning: declaration of 'p' shadows a previous local [-Wshadow=compatible-local]
12469 |             void *p, *n;
      |                   ^
.../linux-user/syscall.c:8975:11: note: shadowed declaration is here
 8975 |     void *p;
      |           ^

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Message-ID: <20230925151029.461358-6-laurent@vivier.eu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>