ARM: s3c: remove orphan declarations from arch/arm/mach-s3c/devs.h

s3c64xx_device_spi1 and s3c64xx_device_spi2 were removed by
commit f1ba938e ("spi: s3c64xx: Delete unused boardfile
helpers"), so remove the declaration, too.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220914034615.1240860-3-cuigaosheng1@huawei.com
Link: https://lore.kernel.org/r/20220926104354.118578-3-krzysztof.kozlowski@linaro.org

'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>