firmware: explicitly include vmalloc.h

firmware: explicitly include vmalloc.h

After some other include file changes, fixes:

drivers/base/firmware_loader/fallback.c: In function 'map_fw_priv_pages':
drivers/base/firmware_loader/fallback.c:232:2: error: implicit declaration of function 'vunmap'; did you mean 'kunmap'? [-Werror=implicit-function-declaration]
  vunmap(fw_priv->data);
  ^~~~~~
  kunmap
drivers/base/firmware_loader/fallback.c:233:18: error: implicit declaration of function 'vmap'; did you mean 'kmap'? [-Werror=implicit-function-declaration]
  fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages, 0,
                  ^~~~
                  kmap
drivers/base/firmware_loader/fallback.c:233:16: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
  fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages, 0,
                ^
drivers/base/firmware_loader/fallback.c: In function 'firmware_loading_store':
drivers/base/firmware_loader/fallback.c:274:4: error: implicit declaration of function 'vfree'; did you mean 'kvfree'? [-Werror=implicit-function-declaration]
    vfree(fw_priv->pages);
    ^~~~~
    kvfree
drivers/base/firmware_loader/fallback.c: In function 'fw_realloc_pages':
drivers/base/firmware_loader/fallback.c:405:15: error: implicit declaration of function 'vmalloc'; did you mean 'kvmalloc'? [-Werror=implicit-function-declaration]
   new_pages = vmalloc(new_array_size * sizeof(void *));
               ^~~~~~~
               kvmalloc
drivers/base/firmware_loader/fallback.c:405:13: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
   new_pages = vmalloc(new_array_size * sizeof(void *));
             ^

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>