Staging: lustre: obdclass: Use kasprintf

This patch uses kasprintf which combines kzalloc and sprintf.
kasprintf also takes care of the size calculation.

Semantic patch used is as follows:

@@
expression a,flag;
expression list args;
statement S;
@@

 a =
- \(kmalloc\|kzalloc\)(...,flag)
+ kasprintf (flag,args)
  <... when != a
  if (a == NULL || ...) S
  ...>
- sprintf(a,args);

Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>