arc: libgloss: Add support of EM Starter Kit board

arc: libgloss: Add support of EM Starter Kit board

These specs files are introduced for EMSK board:

    * emsk1_em4.specs - EMSKv1 with EM4 core, everything in
      ICCM/DCCM memory
    * emsk1_em6.specs - EMSKv1 with EM6 core, everything in
      ICCM/DCCM memory
    * emsk1_em6_ram.specs - EMSKv1 with EM6 core, startup code
      in ICCM and everything else in RAM
    * emsk2.1_em5d.specs - EMSKv2.1 with EM5D core, everything
      in ICCM/DCCM memory
    * emsk2.1_em7d.specs - EMSKv2.1 with EM7D core, everything
      in ICCM/DCCM memory
    * emsk2.1_em7d_ram.specs - EMSKv2.1 with EM7D core, startup
      code in ICCM and everything else in RAM
    * emsk2.2_em7d.specs - EMSKv2.2+ with EM7D core, everything
      in ICCM/DCCM memory
    * emsk2.2_em7d_ram.specs - EMSKv2.2+ with EM7D core, startup
      code in ICCM and everything else in RAM
    * emsk2.2_em9d.specs - EMSKv2.2+ with EM9D core, everything
      in ICCM/DCCM memory
    * emsk2.2_em9d_ram.specs - EMSKv2.2+ with EM9D core, startup
      code in ICCM and everything else in RAM
    * emsk2.2_em11d.specs - EMSKv2.2+ with EM11D core, everything
      in ICCM/DCCM memory
    * emsk2.2_em11d_ram.specs - EMSKv2.2+ with EM11D core, startup
      code in ICCM and everything else in RAM

An example of building an application:

    $ arc-elf32-gcc -mcpu=em -specs=emsk2.2_em11d_ram.specs main.c -o main

Signed-off-by: Vladimir Isaev <vvisaev@gmail.com>
Signed-off-by: Yuriy Kolerov <kolerov93@gmail.com>