command: Fix handling of buffer passing in args[] on 64bit mcu

If the buffer pointer can't fit in a uint32_t then pass a relative
buffer offset instead.  This fixes buffer handling on 64bit linux
mcus.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/generic/misc.h

@@ -6,6 +6,7 @@
 
 struct command_encoder;
 void console_sendf(const struct command_encoder *ce, va_list args);
+void *console_receive_buffer(void);
 
 uint32_t timer_from_us(uint32_t us);
 uint8_t timer_is_before(uint32_t time1, uint32_t time2);