nmeter: do not clamp down %Nc to minimum of 10 (think nmeter "%`nproc`c")

Also, go for unsigned divisions.

function                                             old     new   delta
init_cpu                                              61      73     +12
collect_cpu                                          444     422     -22
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 12/-22)            Total: -10 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/procps/nmeter.c b/procps/nmeter.c
index a01d19a..f0eb367 100644
--- a/procps/nmeter.c
+++ b/procps/nmeter.c
@@ -351,7 +351,7 @@
 enum { CPU_FIELDCNT = 7 };
 S_STAT(cpu_stat)
 	ullong old[CPU_FIELDCNT];
-	int bar_sz;
+	unsigned bar_sz;
 	char bar[1];
 S_STAT_END(cpu_stat)
 
@@ -360,8 +360,8 @@
 	ullong data[CPU_FIELDCNT] = { 0, 0, 0, 0, 0, 0, 0 };
 	unsigned frac[CPU_FIELDCNT] = { 0, 0, 0, 0, 0, 0, 0 };
 	ullong all = 0;
-	int norm_all = 0;
-	int bar_sz = s->bar_sz;
+	unsigned norm_all = 0;
+	unsigned bar_sz = s->bar_sz;
 	char *bar = s->bar;
 	int i;
 
@@ -420,8 +420,8 @@
 {
 	int sz;
 	cpu_stat *s;
-	sz = strtoul(param, NULL, 0); /* param can be "" */
-	if (sz < 10) sz = 10;
+	sz = param[0] ? strtoul(param, NULL, 0) : 10;
+	if (sz <= 0) sz = 1;
 	if (sz > 1000) sz = 1000;
 	s = xzalloc(sizeof(*s) + sz);
 	/*s->bar[sz] = '\0'; - xzalloc did it */