imx: imx8m*: Remove do_reset from board files

Use the `do_reset` implementation of `arch/arm/lib/reset.c` in SPL
instead.  It is very close to what is done here, anyway, and plays
more nicely with the rest of U-Boot than adding a custom `do_reset`
implementation into board files.

`do_reset` from `arch/arm/lib/reset.c` calls `reset_cpu` with 0 as the
addr parameter while the boards are passing WDOG1_BASE_ADDR.  This is
ok because the `reset_cpu` implementation uses WDOG1_BASE_ADDR by
default if 0 is passed in.

Co-Authored-by: Harald Seiler <hws@denx.de>
Signed-off-by: Claudius Heine <ch@denx.de>
Signed-off-by: Harald Seiler <hws@denx.de>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/board/freescale/imx8mm_evk/spl.c b/board/freescale/imx8mm_evk/spl.c
index 5d17f39..4d34622 100644
--- a/board/freescale/imx8mm_evk/spl.c
+++ b/board/freescale/imx8mm_evk/spl.c
@@ -161,12 +161,3 @@
 
 	board_init_r(NULL, 0);
 }
-
-int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
-{
-	puts ("resetting ...\n");
-
-	reset_cpu(WDOG1_BASE_ADDR);
-
-	return 0;
-}
diff --git a/board/freescale/imx8mn_evk/spl.c b/board/freescale/imx8mn_evk/spl.c
index 7aed14c..45417b2 100644
--- a/board/freescale/imx8mn_evk/spl.c
+++ b/board/freescale/imx8mn_evk/spl.c
@@ -114,12 +114,3 @@
 
 	board_init_r(NULL, 0);
 }
-
-int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
-{
-	puts("resetting ...\n");
-
-	reset_cpu(WDOG1_BASE_ADDR);
-
-	return 0;
-}
diff --git a/board/freescale/imx8mp_evk/spl.c b/board/freescale/imx8mp_evk/spl.c
index 0b20668..39c1dae 100644
--- a/board/freescale/imx8mp_evk/spl.c
+++ b/board/freescale/imx8mp_evk/spl.c
@@ -149,12 +149,3 @@
 
 	board_init_r(NULL, 0);
 }
-
-int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
-{
-	puts("resetting ...\n");
-
-	reset_cpu(WDOG1_BASE_ADDR);
-
-	return 0;
-}
diff --git a/board/toradex/verdin-imx8mm/spl.c b/board/toradex/verdin-imx8mm/spl.c
index a5dc540..dc5bd84 100644
--- a/board/toradex/verdin-imx8mm/spl.c
+++ b/board/toradex/verdin-imx8mm/spl.c
@@ -169,12 +169,3 @@
 
 	board_init_r(NULL, 0);
 }
-
-int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
-{
-	puts("resetting ...\n");
-
-	reset_cpu(WDOG1_BASE_ADDR);
-
-	return 0;
-}