compat: fix bug around indentation

Indentation for an if condition was incorrect. Hence upon hitting the error
conditional, the code was not returning the error the value. Fixed in this
change by adding braces with the if conditional. This error was found when
compiling with a newer version of gcc 9.4.0 on ubuntu 20.04.2.

Signed-off-by: Ani Sinha <ani@anisinha.ca>

Author: ani-sinha

rc/python/compat.c

@@ -417,10 +417,10 @@ off_t lseek(int fd, off_t offset, int whence)
 {
     grub_file_t file;
 
-    if (fd >= 0 && fd < 3)
+    if (fd >= 0 && fd < 3) {
         grub_printf("Internal error: Python attempted to seek on stdin, stdout, or stderr.\n");
         return (off_t)-1;
-
+    }
     file = fd_to_file(fd);
     if (!file)
         return (off_t)-1;