iwlwifi: acpi: don't return valid pointer as an ERR_PTR

iwl_acpi_get_wifi_pkg() may return a valid pointer (meaning success),
while `tbl_rev` is invalid (equel to 1).
In this case, we will treat that as an error.
Subsequent "users" of this "error code" may either check for nonzero
(good; pointers are never zero) or negative
(bad; pointers may be "positive") fix that by splitting the if statement.
First check if IS_ERR(wifi_pkg) and then if tbl_rev != 0.

Signed-off-by: Haim Dreyfuss <haim.dreyfuss@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210210142629.1c8c4b58c932.I147373f6fd364606b0282af8d402c722eb917225@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>