change IAR TUSB_CFG_ATTR_USBRAM to _Pragma("location=\".ahb_sram1\"") instead of @ .ahb_sram1 so that we can place it before the variable for a cleaner code

change pipe xfer API buffer from void* to uint8_t*
change FIFO_DEF to have a separated buffer to be compatible with IAR\
refractor IAR data alignment pragma

demos/device/src/tusb_config.h

@@ -123,7 +123,7 @@
 
 #elif __ICCARM__ // compiled with IAR
 
-  #define TUSB_CFG_ATTR_USBRAM  @ ".ahb_sram1"
+  #define TUSB_CFG_ATTR_USBRAM _Pragma("location=\".ahb_sram1\"")
 
 #else