initcall: Move to inline function

The board_r init function was complaining that we are looping through
an array, calling all our tiny init stubs sequentially via indirect
function calls (which can't be speculated, so they are slow).

The solution to that is pretty easy though. All we need to do is inline
the function that loops through the functions and the compiler will
automatically convert almost all indirect calls into direct inlined code.

With this patch, the overall code size drops (by 40 bytes on riscv64)
and boot time should become measurably faster for every target.

Signed-off-by: Alexander Graf <agraf@suse.de>

common/board_r.c

@@ -633,10 +633,7 @@ static int run_main_loop(void)
 }
 
 /*
- * Over time we hope to remove these functions with code fragments and
- * stub functions, and instead call the relevant function directly.
- *
- * We also hope to remove most of the driver-related init and do it if/when
+ * We hope to remove most of the driver-related init and do it if/when
  * the driver is later used.
  *
  * TODO: perhaps reset the watchdog in the initcall function after each call?