spi: spreadtrum adi: add hwspinlock dependency

With CONFIG_HWSPINLOCK=m, the new driver fails to link as a built-in driver:

drivers/spi/spi-sprd-adi.o: In function `sprd_adi_remove':
spi-sprd-adi.c:(.text+0x18): undefined reference to `hwspin_lock_free'
drivers/spi/spi-sprd-adi.o: In function `sprd_adi_probe':
spi-sprd-adi.c:(.text+0xfc): undefined reference to `of_hwspin_lock_get_id'
spi-sprd-adi.c:(.text+0x108): undefined reference to `hwspin_lock_request_specific'
spi-sprd-adi.c:(.text+0x268): undefined reference to `hwspin_lock_free'

This adds a hard Kconfig dependency on HWSPINLOCK for the !COMPILE_TEST
case, and allows compile-testing with HWSPINLOCK completely disabled,
which will then rely on the existing stub API.

Fixes: 7e2903cb ("spi: Add ADI driver for Spreadtrum platform")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>