drivers/i2c: remove !S390 dependency, add missing GENERIC_HARDIRQS dependencies

Remove !S390 dependency from i2c Kconfig, since s390 now supports PCI, HAS_IOMEM
and HAS_DMA, however we need to add a couple of GENERIC_HARDIRQS dependecies to
fix compile and link errors like these:

ERROR: "devm_request_threaded_irq" [drivers/i2c/i2c-smbus.ko] undefined!
ERROR: "devm_request_threaded_irq" [drivers/i2c/busses/i2c-ocores.ko] undefined!

Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 46cde09..e380c6e 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -4,7 +4,6 @@
 
 menuconfig I2C
 	tristate "I2C support"
-	depends on !S390
 	select RT_MUTEXES
 	---help---
 	  I2C (pronounce: I-squared-C) is a slow serial bus protocol used in
@@ -76,6 +75,7 @@
 
 config I2C_SMBUS
 	tristate "SMBus-specific protocols" if !I2C_HELPER_AUTO
+	depends on GENERIC_HARDIRQS
 	help
 	  Say Y here if you want support for SMBus extensions to the I2C
 	  specification. At the moment, the only supported extension is