mini2440: debugging U-Boot with led

debug u-boot with LED1~3 and buzzer

LED1~3 should turn on, and buzzer on, but this commit just turns LED1,
LED3 and buzzer on.

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
mini2440: fix INTSUBMSK bit width issue

register INTSUBMSK has 14 bits in S3C2440, and 11 bits in S3C2410

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
mini2440: set CLKDIVN value properly

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
mini2440: set datasheet recommended MPS vlaues

NOTE(datasheet, page 243):
CLKDIVN should be set carefully not to exceed the limit of HCLK and
PCLK, that is:

Operating Frequency
Fclk Up to 400MHz
Hclk Up to 136MHz
Pclk Up to 68MHz

Currently FCLK is 405 MHz and the division ratio is 1:3:6, so
HCLK = 405 MHz / 3 = 135 MHz (< 136 MHz)
PCLK = 405 MHz / 6 = 67.5 MHz (< 68 MHz)

For how to calculate these values, refer to page 254 of the S3C2440 datasheet

This commit turns on all four leds and buzzer

Signed-off-by: Fudong Bai <fudongbai@gmail.com>