boards/arm/am67/t3-gem-o1: Load .data at its run address.

Nothing copies .data on a RAM/remoteproc image (CONFIG_BOOT_RUNFROMISRAM=y),
so an LMA distinct from the VMA loads initialised data where the code never
reads it.  _sidata was taken before .init_section, putting the load address
sizeof(.init_section) below the run address.

That section is empty in the in-tree configurations, so the fault is latent
today and this change is a no-op for them; it appears as soon as anything lands
in .init_array.

Assisted-by: Claude Code:claude-opus-4-8
Signed-off-by: Ulaş Sertan Kemeç <sertan.usk@gmail.com>

boards/arm/am67/t3-gem-o1/scripts/sdram.ld

@@ -101,7 +101,6 @@ SECTIONS
     } > ddr
 
     _etext = ABSOLUTE(.); /* End of code/read-only sections */
-    _sidata = _etext;    /* Start of initial values for .data (LMA) */
 
     .init_section :
     {
@@ -111,7 +110,7 @@ SECTIONS
         _einit = ABSOLUTE(.);
     } > ddr
 
-    .data : AT ( _sidata )
+    .data :
     {
         _sdata = ABSOLUTE(.);
         *(.data .data.*)