[PATCH] iio/adc: ingenic: fix (MIPS) ingenic-adc build errors

[Randy Dunlap <rdunlap@infradead.org>]

MIPS does not always provide clk*() interfaces and there are no
always-present stubs for them, so depending on "MIPS || COMPILE_TEST"
is not strong enough to prevent build errors.

Likewise MACH_INGENIC_SOC || COMPILE_TEST is not strong enough
since if only COMPILE_TEST=y (with some other MIPS MACH_ or CPU or
BOARD setting), there are still the same build errors.

It looks like depending on MACH_INGENIC_SOC is the only thing that is
sufficient here in order to prevent build errors.

mips-linux-ld: drivers/iio/adc/ingenic-adc.o: in function `jz4770_adc_init_clk_div':
ingenic-adc.c:(.text+0xe4): undefined reference to `clk_get_parent'
mips-linux-ld: drivers/iio/adc/ingenic-adc.o: in function `jz4725b_adc_init_clk_div':
ingenic-adc.c:(.text+0x1b8): undefined reference to `clk_get_parent'

Fixes: 1a78daea107d ("IIO: add Ingenic JZ47xx ADC driver.")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Artur Rojek <contact@artur-rojek.eu>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: linux-mips@vger.kernel.org
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-iio@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
---
 drivers/iio/adc/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20211105.orig/drivers/iio/adc/Kconfig
+++ linux-next-20211105/drivers/iio/adc/Kconfig
@@ -501,7 +501,7 @@ config INA2XX_ADC
 
 config INGENIC_ADC
 	tristate "Ingenic JZ47xx SoCs ADC driver"
-	depends on MIPS || COMPILE_TEST
+	depends on MACH_INGENIC_SOC
 	select IIO_BUFFER
 	help
 	  Say yes here to build support for the Ingenic JZ47xx SoCs ADC unit.