UniPhier platform implements non-TF boot ROM.  Prior to the BL2-AT-EL3
support, BL1 (worked as a pseudo ROM) was needed just for ensuring BL2
is entered at EL1-S.  Now, this platform is able to avoid this waste.

Enable the BL2_AT_EL3 option, and remove BL1.

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

Initial commit for Socionext UniPhier SoC support.  BL1, Bl2, and
BL31 are supported.  Refer to docs/plat/socionext-uniphier.md for
more detais.

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