USBHost, fixed wrong architecture tag (SAM -> SAMD)

libraries/USBHost/library.properties

@@ -5,4 +5,4 @@ maintainer=Arduino <info@arduino.cc>
 sentence=Allows the communication with USB peripherals like mice, keyboards, and thumbdrives. For Arduino DUE only.
 paragraph=The USBHost library allows an Arduino Due board to appear as a USB host, enabling it to communicate with peripherals like USB mice and keyboards. USBHost does not support devices that are connected through USB hubs. This includes some keyboards that have an internal hub.
 url=http://arduino.cc/en/Reference/USBHost
-architectures=sam
+architectures=samd

libraries/USBHost/src/Usb.cpp

@@ -21,7 +21,7 @@ e-mail   :  support@circuitsathome.com
 #include "Usb.h"
 
 
-#ifdef ARDUINO_SAM_ZERO
+#ifdef ARDUINO_SAMD_ZERO
 
 static uint32_t usb_error = 0;
 static uint32_t usb_task_state = USB_DETACHED_SUBSTATE_INITIALIZE;
@@ -854,4 +854,4 @@ uint32_t USBHost::setConf(uint32_t addr, uint32_t ep, uint32_t conf_value) {
         return ( ctrlReq(addr, ep, bmREQ_SET, USB_REQUEST_SET_CONFIGURATION, conf_value, 0x00, 0x0000, 0x0000, 0x0000, NULL, NULL));
 }
 
-#endif //ARDUINO_SAM_ZERO
+#endif //ARDUINO_SAMD_ZERO