treewide: convert bd_t to struct bd_info by coccinelle

The Linux coding style guide (Documentation/process/coding-style.rst)
clearly says:

  It's a **mistake** to use typedef for structures and pointers.

Besides, using typedef for structures is annoying when you try to make
headers self-contained.

Let's say you have the following function declaration in a header:

  void foo(bd_t *bd);

This is not self-contained since bd_t is not defined.

To tell the compiler what 'bd_t' is, you need to include <asm/u-boot.h>

  #include <asm/u-boot.h>
  void foo(bd_t *bd);

Then, the include direcective pulls in more bloat needlessly.

If you use 'struct bd_info' instead, it is enough to put a forward
declaration as follows:

  struct bd_info;
  void foo(struct bd_info *bd);

Right, typedef'ing bd_t is a mistake.

I used coccinelle to generate this commit.

The semantic patch that makes this change is as follows:

  <smpl>
  @@
  typedef bd_t;
  @@
  -bd_t
  +struct bd_info
  </smpl>

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/board/boundary/nitrogen6x/nitrogen6x.c b/board/boundary/nitrogen6x/nitrogen6x.c
index b3b121b..5b2d675 100644
--- a/board/boundary/nitrogen6x/nitrogen6x.c
+++ b/board/boundary/nitrogen6x/nitrogen6x.c
@@ -321,7 +321,7 @@
 	return 0;
 }
 
-int board_eth_init(bd_t *bis)
+int board_eth_init(struct bd_info *bis)
 {
 	uint32_t base = IMX_FEC_BASE;
 	struct mii_dev *bus = NULL;