arm64: renesas: Deduplicate board_early_init_f()

Introduce common weak board_early_init_f() in rcar64-common.c
which is the default implementation in case there is no other
board specific board_early_init_f(). Remove board_early_init_f()
from Salvator-X, ULCB and Draak boards where this function is
empty.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/board/renesas/common/rcar64-common.c b/board/renesas/common/rcar64-common.c
index 74ec0a4..69229ea 100644
--- a/board/renesas/common/rcar64-common.c
+++ b/board/renesas/common/rcar64-common.c
@@ -65,3 +65,8 @@
 {
 	return 0;
 }
+
+int __weak board_early_init_f(void)
+{
+	return 0;
+}
diff --git a/board/renesas/draak/draak.c b/board/renesas/draak/draak.c
index 8521349..564cf43 100644
--- a/board/renesas/draak/draak.c
+++ b/board/renesas/draak/draak.c
@@ -10,11 +10,6 @@
 #include <asm/arch/rcar-mstp.h>
 #include <asm/arch/renesas.h>
 
-int board_early_init_f(void)
-{
-	return 0;
-}
-
 #define HSUSB_MSTP704		BIT(4)	/* HSUSB */
 
 /* HSUSB block registers */
diff --git a/board/renesas/salvator-x/salvator-x.c b/board/renesas/salvator-x/salvator-x.c
index 60f8b94..6d33d00 100644
--- a/board/renesas/salvator-x/salvator-x.c
+++ b/board/renesas/salvator-x/salvator-x.c
@@ -12,11 +12,6 @@
 #include <asm/arch/renesas.h>
 #include <init.h>
 
-int board_early_init_f(void)
-{
-	return 0;
-}
-
 #define HSUSB_MSTP704		BIT(4)	/* HSUSB */
 
 /* HSUSB block registers */
diff --git a/board/renesas/ulcb/ulcb.c b/board/renesas/ulcb/ulcb.c
index 3f6db0e..d02e5d0 100644
--- a/board/renesas/ulcb/ulcb.c
+++ b/board/renesas/ulcb/ulcb.c
@@ -13,11 +13,6 @@
 
 #define HSUSB_MSTP704		BIT(4)	/* HSUSB */
 
-int board_early_init_f(void)
-{
-	return 0;
-}
-
 /* HSUSB block registers */
 #define HSUSB_REG_LPSTS			0xE6590102
 #define HSUSB_REG_LPSTS_SUSPM_NORMAL	BIT(14)