spi: armada-3700: Remove spi_master_put in a3700_spi_remove()

The call to spi_master_put() in a3700_spi_remove() is redundant since
the master is registered using devm_spi_register_master() and no
reference hold by using spi_master_get() in a3700_spi_remove().

This is detected by Coccinelle semantic patch.

Fixes: 5762ab71 ("spi: Add support for Armada 3700 SPI Controller")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>