Improve the Kconfig help text of the follwing i2c drivers:
* busses/i2c-pca-isa.c
* chips/pcf8574.c
* chips/pcf8591.c
These are hard to detect and building them into the kernel
results in long delays at boot.

March 2006, thread "I2C_PCA_ISA causes boot delays"
http://marc.theaimsgroup.com/?l=linux-kernel&m=114360399415744&w=2

April 2006, thread "i2c-related 1-minute hang during bootup"
http://marc.theaimsgroup.com/?l=linux-kernel&m=114640992330721&w=2Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>