xscale: better fix for debug_handler.bin

Generate a C struct with the data, and use that, instead of an
assembly language file.  The assembly language causes issues on
Darwin and MS-Windows, which don't necessarily use GNU AS; or
if they do, don't necessarily use its ELF syntax.

It's also better in two other ways:  fewer global symbols; and
the init-time size check gets optimized away at compile time.
(Unless it fails, in which case bigger chunks of the file vanish.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/target/xscale.h

@@ -170,10 +170,4 @@ enum
 
 #define ERROR_XSCALE_NO_TRACE_DATA	(-1500)
 
-/* This XScale "debug handler" is loaded into the processor's
- * mini-ICache, which is 2K of code writable only via JTAG.
- */
-extern const uint8_t xscale_debug_handler[];
-extern const uint32_t xscale_debug_handler_size;
-
 #endif /* XSCALE_H */