NFC: st-nci: spi: Drop two useless checks in ACPI probe path

When st_nci_spi_acpi_request_resources() gets called we
already know that the entries in ->acpi_match_table have
matched ACPI ID of the device.
In addition spi_device pointer cannot be NULL in any case
(otherwise SPI core would not call ->probe() for the driver
in the first place).

Drop the two useless checks from the driver.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>