procps: code shrink

function                                             old     new   delta
skip_whitespace_if_prefixed_with                       -      17     +17
procps_read_smaps                                    911     854     -57
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/1 up/down: 17/-57)            Total: -40 bytes

Signed-off-by: Martin Lewis <martin.lewis.x84@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/libbb/procps.c b/libbb/procps.c
index af3ad86..4cc3cb2 100644
--- a/libbb/procps.c
+++ b/libbb/procps.c
@@ -177,6 +177,15 @@
 }
 #endif
 
+static char* skip_whitespace_if_prefixed_with(char *buf, const char *prefix)
+{
+	char *tp = is_prefixed_with(buf, prefix);
+	if (tp) {
+		tp = skip_whitespace(tp);
+	}
+	return tp;
+}
+
 #if ENABLE_FEATURE_TOPMEM || ENABLE_PMAP
 int FAST_FUNC procps_read_smaps(pid_t pid, struct smaprec *total,
 		void (*cb)(struct smaprec *, void *), void *data)
@@ -207,8 +216,7 @@
 		char *tp, *p;
 
 #define SCAN(S, X) \
-		if ((tp = is_prefixed_with(buf, S)) != NULL) {       \
-			tp = skip_whitespace(tp);                    \
+		if ((tp = skip_whitespace_if_prefixed_with(buf, S)) != NULL) { \
 			total->X += currec.X = fast_strtoul_10(&tp); \
 			continue;                                    \
 		}