system/nxinit: fix missing blank line after declaration in parser.c

init_parse_config_file() declares 'r' inside the read loop with no
blank line before the following 'if (r < 0)' statement, violating the
NuttX coding standard (nxstyle: "Missing blank line after
declarations"). checkpatch.sh runs a whole-file nxstyle check on any
file a commit touches, not diff-only, so this pre-existing issue
surfaced on this PR's CI once parser.c was touched again.

Assisted-by: GitHubCopilot:claude-sonnet-5
Signed-off-by: wangjianyu3 <wangjianyu3@xiaomi.com>

system/nxinit/parser.c

@@ -269,6 +269,7 @@ int init_parse_config_file(FAR const struct parser_s *parser,
   for (; ; )
     {
       ssize_t r = read(fd, &buf[n], sizeof(buf) - n);
+
       if (r < 0)
         {
           if (errno == EINTR)