fix(demo): increase number of dynamic threads (#150)

Depending on the platform, these get set to very low values.

Increase the number of dynamic POSIX threads and mutexes, so
the demo can run fine on b_u585i_iot02a.

Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>

Author: casaroli

src/samples/demo/zephyr/prj.conf

@@ -16,6 +16,10 @@ CONFIG_DYNAMIC_THREAD_STACK_SIZE=8192
 CONFIG_MAIN_STACK_SIZE=8192
 CONFIG_COMMON_LIBC_MALLOC_ARENA_SIZE=-1
 
+# pthreads
+CONFIG_MAX_PTHREAD_MUTEX_COUNT=8
+CONFIG_POSIX_THREAD_THREADS_MAX=8
+
 # Ocre configuration
 CONFIG_OCRE=y
 CONFIG_OCRE_TIMER=y