acpi: Replace weird use of PTR_RET.
acpi: Replace weird use of PTR_RET.

This functions is really weird.  It sets rc to -ENOMEM, then overrides
it.  It was converted to PTR_RET in a1458187 when it should have
simply been rewritten.

This version makes it more explicit, with a single IS_ERR() test.

Cc: Alexandru Gheorghiu <d0a91e316e80e0c7f9479d1fc49e188e326bc9cf@gmail.com>
Signed-off-by: Rusty Russell <df9728c9e5104131c08c7adb03af425394842596@rustcorp.com.au>
Acked-by: Rafael J. Wysocki <27ffc44a8ec6a212fba98cfc3246c6ce8ab131e0@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs