various fixes (#49)

* libs: libc: math: Fix tanh() math functions
* drivers: mtd: smart: Fix trivial debug message in smartfs
* binfmt: libelf: Fix fd not closed on error
* binfmt: Fix stack memory leak on error
* fs: romfs: Fix private data not free on error
* sched: group: Fix reference after free memory
* sched: clock: Fix clock sync

Fix clock sync when CONFIG_RTC_HIRES is enabled

libs/libc/math/lib_tanh.c

@@ -44,6 +44,6 @@ double tanh(double x)
   double x0 = exp(x);
   double x1 = 1.0 / x0;
 
-  return ((x0 + x1) / (x0 - x1));
+  return ((x0 - x1) / (x0 + x1));
 }
 #endif

libs/libc/math/lib_tanhf.c

@@ -40,5 +40,5 @@ float tanhf(float x)
   float x0 = expf(x);
   float x1 = 1.0F / x0;
 
-  return ((x0 + x1) / (x0 - x1));
+  return ((x0 - x1) / (x0 + x1));
 }

libs/libc/math/lib_tanhl.c

@@ -44,6 +44,6 @@ long double tanhl(long double x)
   long double x0 = exp(x);
   long double x1 = 1.0 / x0;
 
-  return ((x0 + x1) / (x0 - x1));
+  return ((x0 - x1) / (x0 + x1));
 }
 #endif