Fix errors in strings

Found with codespell:
codespell -w src/cm108.c src/direwolf.c

Author: dforsi

src/cm108.c

@@ -304,7 +304,7 @@ static void usage(void)
 	dw_printf ("which ones can be used for GPIO PTT.\n");
 #endif
 	dw_printf ("\n");
-	dw_printf ("Specify the HID device path to test the PTT fuction.\n");
+	dw_printf ("Specify the HID device path to test the PTT function.\n");
 	dw_printf ("Its state should change once per second.\n");
 #if __WIN32__
 	dw_printf ("You might need to quote the path depending on the command processor.\n");

src/direwolf.c

@@ -382,7 +382,7 @@ int main (int argc, char *argv[])
 	if (getuid() == 0 || geteuid() == 0) {
 	    text_color_set(DW_COLOR_ERROR);
 	    dw_printf ("Dire Wolf requires only privileges available to ordinary users.\n");
-	    dw_printf ("Running this as root is an unnecssary security risk.\n");
+	    dw_printf ("Running this as root is an unnecessary security risk.\n");
 	}
 #endif