linker_script: move .data section to bl_common.ld.h

Move the data section to the common header.

I slightly tweaked some scripts as follows:

[1] bl1.ld.S has ALIGN(16). I added DATA_ALIGN macro, which is 1
    by default, but overridden by bl1.ld.S. Currently, ALIGN(16)
    of the .data section is redundant because commit 412865907699
    ("Fix boot failures on some builds linked with ld.lld.") padded
    out the previous section to work around the issue of LLD version
    <= 10.0. This will be fixed in the future release of LLVM, so
    I am keeping the proper way to align LMA.

[2] bl1.ld.S and bl2_el3.ld.S define __DATA_RAM_{START,END}__ instead
    of __DATA_{START,END}__. I put them out of the .data section.

[3] SORT_BY_ALIGNMENT() is missing tsp.ld.S, sp_min.ld.S, and
    mediatek/mt6795/bl31.ld.S. This commit adds SORT_BY_ALIGNMENT()
    for all images, so the symbol order in those three will change,
    but I do not think it is a big deal.

Change-Id: I215bb23c319f045cd88e6f4e8ee2518c67f03692
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/bl2/bl2.ld.S b/bl2/bl2.ld.S
index 17475f0..37849c3 100644
--- a/bl2/bl2.ld.S
+++ b/bl2/bl2.ld.S
@@ -77,17 +77,7 @@
      */
     __RW_START__ = . ;
 
-    /*
-     * .data must be placed at a lower address than the stacks if the stack
-     * protector is enabled. Alternatively, the .data.stack_protector_canary
-     * section can be placed independently of the main .data section.
-     */
-    .data . : {
-        __DATA_START__ = .;
-        *(SORT_BY_ALIGNMENT(.data*))
-        __DATA_END__ = .;
-    } >RAM
-
+    DATA_SECTION >RAM
     STACK_SECTION >RAM
     BSS_SECTION >RAM
     XLAT_TABLE_SECTION >RAM