Fix some type mismatches.

Upstream bug: https://sourceforge.net/p/ifp-driver/patches/12/

--- libifp-1.0.0.2/src/ifp_os_libusb.c	2005-08-22 04:03:56.000000000 +0100
+++ libifp-1.0.0.2/src/ifp_os_libusb.c	2025-07-04 00:25:17.363567870 +0100
@@ -20,7 +20,7 @@
 	char * ob, int max_o, const char * ib, int max_i)
 {
 	int i=0, e=0;
-	char const * ibb = (char const *)ib;
+	char * ibb = (char *)ib;
 	char * obb = (char *)ob;
 	size_t i_n = max_i;
 	size_t o_n = max_o;
--- libifp-1.0.0.2/src/userfile.c	2005-08-22 04:03:56.000000000 +0100
+++ libifp-1.0.0.2/src/userfile.c	2025-07-04 00:24:35.771617323 +0100
@@ -947,7 +947,7 @@
 	return i;
 }
 
-int file_compare_fts(const FTSENT * const*p1, const FTSENT * const*p2)
+int file_compare_fts(const FTSENT **p1, const FTSENT **p2)
 {
 	if (p1 == NULL) { ifp_err("p1 shouldn't be NULL"); return 0; }
 	if (p2 == NULL) { ifp_err("p2 shouldn't be NULL"); return 0; }