powerpc/rtas_flash: Eliminate possible double free
The function initialize_flash_pde_data is only called four times. All four
calls are in the function rtas_flash_init, and on the failure of any of the
calls, remove_flash_pde is called on the third argument of each of the
calls. There is thus no need for initialize_flash_pde_data to call
remove_flash_pde on the same argument. remove_flash_pde kfrees the data
field of its argument, and does not clear that field, so this amounts ot a
possible double free.
A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)