drivers/leds/leds-pca9532.c: change driver name to be unique

This driver handles the variants pca9530-pca9533, so it chose the name
"pca953x".  However, there is a gpio driver which decided on the same
name.  As a result, those two can't be loaded at the same time.  Add a
subsystem prefix to make the driver name unique.  Device matching will not
suffer, because both are I2C drivers which match using a
i2c_device_id-table which is not altered.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>