The atp870u driver is the largest stack eater reported by checkstack
(on x86_864, allmodconfig). This converts the offending function
to kmalloc+kfree struct atp_unit instead of allocating it on the stack.
Was:
0x0000164c atp870u_probe [atp870u]: 3176
Now:
0x0000164c atp870u_probe [atp870u]: 408
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>