linker_script: move bss section to bl_common.ld.h

Move the bss section to the common header. This adds BAKERY_LOCK_NORMAL
and PMF_TIMESTAMP, which previously existed only in BL31. This is not
a big deal because unused data should not be compiled in the first
place. I believe this should be controlled by BL*_SOURCES in Makefiles,
not by linker scripts.

I investigated BL1, BL2, BL2U, BL31 for plat=fvp, and BL2-AT-EL3,
BL31, BL31 for plat=uniphier. I did not see any more  unexpected
code addition.

The bss section has bigger alignment. I added BSS_ALIGN for this.

Currently, SORT_BY_ALIGNMENT() is missing in sp_min.ld.S, and with this
change, the BSS symbols in SP_MIN will be sorted by the alignment.
This is not a big deal (or, even better in terms of the image size).

Change-Id: I680ee61f84067a559bac0757f9d03e73119beb33
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>