axi_cfd: Fix depends for regmap_spi

[gastmaier]

PR Description

Detected by run pr #2906
Batch resolve for other drivers as well:

$grep -rnw devm_regmap_init_spi
ad9144.c:       st->map = devm_regmap_init_spi(spi, &ad9144_regmap_config); # OK
ad9162.c:       st->map = devm_regmap_init_spi(spi, &ad9162_regmap_config); # NOK
ad9172.c:       st->map = devm_regmap_init_spi(spi, &ad9172_regmap_config); # NOK
ad9783.c:       phy->regmap = devm_regmap_init_spi(spi, &ad9783_regmap_config); # NOK
adf4030.c:      st->regmap = devm_regmap_init_spi(spi, &adf4030_regmap_config); # OK
adf4371.c:      regmap = devm_regmap_init_spi(spi, &adf4371_regmap_config); # ÒK
adf4377.c:      regmap = devm_regmap_init_spi(spi, &adf4377_regmap_config); # OK
adl5960.c:      dev->regmap = devm_regmap_init_spi(spi, &adl5960_regmap_config); # OK
admv4420.c:     regmap = devm_regmap_init_spi(spi, &admv4420_regmap_config); # OK

Same as #2790

None touched are upstream.
https://lore.kernel.org/linux-iio/?q=CF_AXI_DDS

PR Type

• Bug fix (a change that fixes an issue)
• New feature (a change that adds new functionality)
• Breaking change (a change that affects other repos or cause CIs to fail)

PR Checklist

• I have conducted a self-review of my own code changes
• I have tested the changes on the relevant hardware
• I have updated the documentation outside this repo accordingly (if there is the case)