Rename various microkernel source files

Now spells out the name of the associated microkernel object in full.
Also renames file containing FIFO code to correspond to the associated
public include file (microkernel/fifo.h).

Change-Id: I47f7a2ca01e0feff8f499acda0000fe475e7ee5a
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>

doc/object/object_microkernel.rst

@@ -299,7 +299,7 @@ Definition
 ==========
 
 The microkernel semaphore is defined in
-:file:`kernel/microkernel/k_sema.c` and are an implementation of
+:file:`kernel/microkernel/k_semaphore.c` and are an implementation of
 traditional counting semaphores. Semaphores are used to synchronize
 application task activities.
 

kernel/microkernel/Makefile

@@ -6,16 +6,16 @@ obj-y += global.o
 obj-y += cmdPkt.o
 obj-y += movedata.o
 obj-y += ticker.o
-obj-y += k_memmap.o
-obj-y += k_mempool.o
+obj-y += k_memory_map.o
+obj-y += k_memory_pool.o
 obj-y += k_irq.o
 obj-y += k_nop.o
 obj-y += k_offload.o
 obj-y += k_event.o
-obj-y += k_mbox.o
+obj-y += k_mailbox.o
 obj-y += k_mutex.o
-obj-y += k_queue.o
-obj-y += k_sema.o
+obj-y += k_fifo.o
+obj-y += k_semaphore.o
 obj-y += k_timer.o
 obj-y += k_pipe_buffer.o k_pipe.o k_pipe_get.o \
 	k_pipe_put.o k_pipe_util.o k_pipe_xfer.o