nasm_warnf() -> nasm_warn()

We want to strongly encourage writers of warnings to create warning
categories, so remove the flagless nasm_warn() and change nasm_warnf()
to nasm_warn().

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
diff --git a/asm/stdscan.c b/asm/stdscan.c
index ee6d044..dbe0fd5 100644
--- a/asm/stdscan.c
+++ b/asm/stdscan.c
@@ -173,7 +173,7 @@
              *!  indicate a mistake in the source code.  Currently only the MASM
              *!  \c{PTR} keyword is recognized.
              */
-            nasm_warnf(ERR_PASS1|WARN_PTR, "`%s' is not a NASM keyword",
+            nasm_warn(ERR_PASS1|WARN_PTR, "`%s' is not a NASM keyword",
                        tv->t_charptr);
         }