arch: m68k: Implement relocation

Implement relocation for M68K. Perform all the updates in start.S
relocate_code in assemby, since it is a simple matter of traversing
the dynsym table and adding relocation offset - MONITOR_BASE to all
the items in that table. The necessity to deal with MONITOR_BASE is
a specific of M68K, where the ELF entry point is at offset 0x400,
which is the MONITOR_BASE, while TEXT_BASE is at offset 0 .

This also removes the one last user of NEEDS_MANUAL_RELOC, so that
could be finally cleaned up .

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 1911563..587edd5 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -4,8 +4,8 @@
 config SYS_ARCH
 	default "m68k"
 
-config NEEDS_MANUAL_RELOC
-	def_bool y
+config STATIC_RELA
+	default y
 
 # processor family
 config MCF520x