Introduce generic shutdown_free() and remove redundant internal_shutdown()

The former will be useful in cases where cleanup equals a simple call to free().

Corresponding to flashrom svn r1848.
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

flash.h

@@ -54,6 +54,7 @@ typedef uint32_t chipsize_t; /* Able to store the number of bytes of any support
 #define PRIuCHIPSIZE PRIu32
 
 int register_shutdown(int (*function) (void *data), void *data);
+int shutdown_free(void *data);
 void *programmer_map_flash_region(const char *descr, uintptr_t phys_addr, size_t len);
 void programmer_unmap_flash_region(void *virt_addr, size_t len);
 void programmer_delay(unsigned int usecs);

flashrom.c

@@ -373,6 +373,12 @@ static bool all_skipped = true;
 
 static int check_block_eraser(const struct flashctx *flash, int k, int log);
 
+int shutdown_free(void *data)
+{
+	free(data);
+	return 0;
+}
+
 /* Register a function to be executed on programmer shutdown.
  * The advantage over atexit() is that you can supply a void pointer which will
  * be used as parameter to the registered function upon programmer shutdown.

internal.c

@@ -158,11 +158,6 @@ static const struct par_master par_master_internal = {
 
 enum chipbustype internal_buses_supported = BUS_NONE;
 
-static int internal_shutdown(void *data)
-{
-	return 0;
-}
-
 int internal_init(void)
 {
 #if __FLASHROM_LITTLE_ENDIAN__
@@ -237,8 +232,6 @@ int internal_init(void)
 
 	if (rget_io_perms())
 		return 1;
-	if (register_shutdown(internal_shutdown, NULL))
-		return 1;
 
 	/* Default to Parallel/LPC/FWH flash devices. If a known host controller
 	 * is found, the host controller init routine sets the