Fix the libusb and hidapi includes

The libusb and hidapi pkg-config files already add the subdirectory to
the header search path with:

   -I/usr/include/libusb-1.0
   -I/usr/include/hidapi

Therefore, using the subdirectory in the include statement is wrong. In
practice, this usualy works fine by accident, because the base directory
(/usr/include) is typically listed in the default search path of the
compiler. But that's not always true. For example when cross-compiling
or when using the PKG_CONFIG_LIBDIR environment variable.

src/atomics_cobalt.c

@@ -30,7 +30,7 @@
 #ifdef _WIN32
 #define NOGDI
 #endif
-#include <libusb-1.0/libusb.h>
+#include <libusb.h>
 #endif
 
 #include "atomics_cobalt.h"

src/usbhid.c

@@ -45,9 +45,9 @@
 #ifdef _WIN32
 #define NOGDI
 #endif
-#include <libusb-1.0/libusb.h>
+#include <libusb.h>
 #elif defined(USE_HIDAPI)
-#include <hidapi/hidapi.h>
+#include <hidapi.h>
 #endif
 
 #include <libdivecomputer/usbhid.h>