fix a very minor issue in units.h but it does not change anything in current code

(this code is not in use currently)
Fixes #9492
https://gitlab.com/kicad/code/kicad/issues/9492

pcb_calculator/transline/units.h

@@ -32,8 +32,6 @@
 #ifndef HAVE_CMATH_ASINH
 inline double asinh( double x )
 {
-    if( x==0.0 ) return sqrt( -1.0 );
-
     return log( x+sqrt(x*x+1) );
 }
 #endif
@@ -42,7 +40,7 @@ inline double asinh( double x )
 inline double acosh( double x )
 {
     // must be x>=1, if not return Nan (Not a Number)
-    if( !(x>=1.0) ) return sqrt( -1.0 );
+    if( !(x>1.0) ) return sqrt( -1.0 );
 
     // return only the positive result (as sqrt does).
     return log( x+sqrt(x*x-1.0) );