tests: logging: syst: Add testcases for mipi syst.

Adding testcases for mipi syst logging format. Excluding
problem architectures from the testcase as SYS-T does not
support 64-bit or big endian architectures. The posix arch
is excluded as it generates numerous anomalous runtime messages
because it does not have the means to determine when data
resides in the rodata section.

Signed-off-by: Aastha Grover <aastha.grover@intel.com>