chore(bl): add UNALIGNED symbols for TEXT/RODATA

Add symbols to mark end of TEXT/RODATA before page alignment.
Similar change was done by commit 8d69a03f6a7d ("Various
improvements/cleanups on the linker scripts") for
RO_END/COHERENT_RAM. These symbols help to know how much free
space is in the final binary because of page alignment.

Also show all *UNALIGNED__ symbols via poetry.
For example:
poetry run memory -p zynqmp -b debug

Change-Id: I322beba37dad76be9f4e88ca7e5b3eff2df7d96e
Signed-off-by: Michal Simek <michal.simek@amd.com>
diff --git a/bl2/bl2.ld.S b/bl2/bl2.ld.S
index 5f689d5..db83a0c 100644
--- a/bl2/bl2.ld.S
+++ b/bl2/bl2.ld.S
@@ -35,6 +35,7 @@
 
         *(SORT_BY_ALIGNMENT(.text*))
         *(.vectors)
+        __TEXT_END_UNALIGNED__ = .;
 
         . = ALIGN(PAGE_SIZE);
 
@@ -57,6 +58,7 @@
 
         RODATA_COMMON
 
+        __RODATA_END_UNALIGNED__ = .;
         . = ALIGN(PAGE_SIZE);
 
         __RODATA_END__ = .;