cleanup whitespaces

asm/preproc.c predominantly uses spaces, but these three lines
use tabs.

Author: sorokin

asm/preproc.c

@@ -7643,9 +7643,9 @@ static Token *pp_tokline(void)
                         free_tlist(m->iline);
                         nasm_free(m->paramlen);
                         fm->in_progress = 0;
-			m->params = NULL;
-			m->iline = NULL;
-			m->paramlen = NULL;
+                        m->params = NULL;
+                        m->iline = NULL;
+                        m->paramlen = NULL;
                     }
                 }