tpm_tis_spi: Pass the SPI IRQ down to the driver

An SPI TPM device managed directly on an embedded board using
the SPI bus and some GPIO or similar line as IRQ handler will
pass the IRQn from the TPM device associated with the SPI
device. This is already handled by the SPI core, so make sure
to pass this down to the core as well.

(The TPM core habit of using -1 to signal no IRQ is dubious
(as IRQ 0 is NO_IRQ) but I do not want to mess with that
semantic in this patch.)

Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>