firmware: Google VPD: Fix memory allocation error handling

This patch fixes several issues:
   - if the 1st 'kzalloc' fails, we dereference a NULL pointer
   - if the 2nd 'kzalloc' fails, there is a memory leak
   - if 'sysfs_create_bin_file' fails there is also a memory leak

Fix it by adding a test after the first memory allocation and some error
handling paths to correctly free memory if needed.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>