Misc. typo fixes

Found via `codespell -q 3 -w -L ith,als,dum,nd,amin,nto,wis,ba -S ./relapack,./kernel,./lapack-netlib`

interface/zaxpy.c

@@ -99,7 +99,7 @@ void CNAME(blasint n, FLOAT *ALPHA, FLOAT *x, blasint incx, FLOAT *y, blasint in
   //disable multi-thread when incx==0 or incy==0
   //In that case, the threads would be dependent.
   //
-  //Temporarily work-around the low performance issue with small imput size &
+  //Temporarily work-around the low performance issue with small input size &
   //multithreads.
   if (incx == 0 || incy == 0 || n <= MULTI_THREAD_MINIMAL)
 	  nthreads = 1;