hwmon: (ltq-cputemp) restrict it to SOC_XWAY

Building with SENSORS_LTQ_CPUTEMP=y with SOC_FALCON=y causes build
errors since FALCON does not support the same features as XWAY.

Change this symbol to depend on SOC_XWAY since that provides the
necessary interfaces.

Repairs these build errors:

../drivers/hwmon/ltq-cputemp.c: In function 'ltq_cputemp_enable':
../drivers/hwmon/ltq-cputemp.c:23:9: error: implicit declaration of function 'ltq_cgu_w32'; did you mean 'ltq_ebu_w32'? [-Werror=implicit-function-declaration]
   23 |         ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR);
../drivers/hwmon/ltq-cputemp.c:23:21: error: implicit declaration of function 'ltq_cgu_r32'; did you mean 'ltq_ebu_r32'? [-Werror=implicit-function-declaration]
   23 |         ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR);
../drivers/hwmon/ltq-cputemp.c: In function 'ltq_cputemp_probe':
../drivers/hwmon/ltq-cputemp.c:92:31: error: 'SOC_TYPE_VR9_2' undeclared (first use in this function)
   92 |         if (ltq_soc_type() != SOC_TYPE_VR9_2)

Fixes: 7074d0a9 ("hwmon: (ltq-cputemp) add cpu temp sensor driver")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Florian Eckert <fe@dev.tdt.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: linux-hwmon@vger.kernel.org
Link: https://lore.kernel.org/r/20220509234740.26841-1-rdunlap@infradead.orgSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/Kconfig

@@ -960,7 +960,7 @@ config SENSORS_LTC4261
 
 config SENSORS_LTQ_CPUTEMP
 	bool "Lantiq cpu temperature sensor driver"
-	depends on LANTIQ
+	depends on SOC_XWAY
 	help
 	  If you say yes here you get support for the temperature
 	  sensor inside your CPU.