ARM: i.MX5x CSPI: Fixed clock name for CSPI

This patch also includes fix CSPI ID for i.MX53. ID should be 2,
because IDs 0 and 1 are occupied by eCSPI.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>