arc: emsdp: Add more platform-specific compiler options

arc: emsdp: Add more platform-specific compiler options

Even though EM SDP is FPGA-based board and different FPGA
images (known as .bit-files) are awailable for the board still
there's a common subset of options we may rely on for all configs.

These are:
 * Normalizer
 * Swap instructions
 * Simple multiplier
 * Barrel-shifter
 * Floating-point unit
 * Shorter instructions (code density)

This among other improvements allows to compile code with
64-bit divisions, see [1].

[1] https://patchwork.ozlabs.org/patch/1156541/

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Kever Yang <kever.yang@rock-chips.com>