HAL at update of fan speed reads Switch's temperature sensors.
Sensors read:
-FPGA
-PLL (was read before to drive PWM for fan)
-Power supply left
-Power supply right

Additionally:
-add hal_temp_sensors structure to hal shmem, add current temperature and
 threshold values (to be implemented in later commits)
-increment HAL_SHMEM_VERSION
-update hal_shmem.h in ppsi
-update dump_shmem with new structure, add specific type for temperature
 sensors
-in hal_ports.c
 --rename struct wrs_shm_head *head to struct wrs_shm_head *hal_shmem_hdr
 --remove void *hal_port_shmem as not needed,
 --make struct hal_shmem_header *hal_shmem extern, defined in hal_main.c
Signed-off-by: Adam Wujek <adam.wujek@cern.ch>