serial/imx: get rid of the uses of cpu_is_mx1()

The patch removes all the uses of cpu_is_mx1().  Instead, it uses
the .id_table of platform_driver to distinguish the uart device type,
IMX1_UART and IMX21_UART.  The IMX21_UART type runs on all i.mx
except i.mx1.

A couple of !cpu_is_mx1 logic gets turned into is_imx21_uart,
as the codes wrapped there are really IMX21 type uart specific.

It also removes macro MX1_UCR3_REF25 and MX1_UCR3_REF30 which are
not used anywhere.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/arm/mach-imx/clock-imx1.c b/arch/arm/mach-imx/clock-imx1.c
index dcc4172..4aabeb2 100644
--- a/arch/arm/mach-imx/clock-imx1.c
+++ b/arch/arm/mach-imx/clock-imx1.c
@@ -587,9 +587,9 @@
 	_REGISTER_CLOCK(NULL, "mma", mma_clk)
 	_REGISTER_CLOCK("imx_udc.0", NULL, usbd_clk)
 	_REGISTER_CLOCK(NULL, "gpt", gpt_clk)
-	_REGISTER_CLOCK("imx-uart.0", NULL, uart_clk)
-	_REGISTER_CLOCK("imx-uart.1", NULL, uart_clk)
-	_REGISTER_CLOCK("imx-uart.2", NULL, uart_clk)
+	_REGISTER_CLOCK("imx1-uart.0", NULL, uart_clk)
+	_REGISTER_CLOCK("imx1-uart.1", NULL, uart_clk)
+	_REGISTER_CLOCK("imx1-uart.2", NULL, uart_clk)
 	_REGISTER_CLOCK("imx-i2c.0", NULL, i2c_clk)
 	_REGISTER_CLOCK("imx1-cspi.0", NULL, spi_clk)
 	_REGISTER_CLOCK("imx1-cspi.1", NULL, spi_clk)