Add support for the Meta architecture

Meta cores are 32-bit, hardware multithreaded, general purpose, embedded
processors which also feature a DSP instruction set, and can be found in
many digital radios. They are capable of running different operating
systems on different hardware threads, for example a digital radio might
run RTOSes for DAB decoding and audio decoding on 3 hardware threads,
and run Linux on the 4th hardware thread to manage the user interface,
networking etc. HTPs are also capable of running SMP Linux on multiple
hardware threads.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
libm: Add support for the Meta architecture

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
metag: Add support for loading shared objects into core memories.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
extra/locale: Mark __codeset_8_bit_t as packed for Meta

gen_ldc writes offsets into the __locale_mmap_t structure. This
relies on the host system having the same struct offsets as the
target. On Meta, the structs are always aligned to a multiple of
4 bytes, and for these targets it is required for the struct to
be packed so that it is more likely to match the host system
(typically x86 which does not align structs).

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
metag: Add NPTL support

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>