DaVinci: fix ddr2 vtp i/o calibration

Previously, only the low 5 bits (NCH) were being transfered
from DDRVTPR to DDRVTPIOCR, the bits 5-9 where zeroed.

VTP_RECAL should be bit 15, not 18.

The only mainline board affected by this change is davinci_sonata.
The other Davinci boards define CONFIG_SKIP_LOWLEVEL_INIT.

However, if the program that loads u-boot on these boards
copied the code from u-boot, they will need fixed as well.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

Please get tested by acks before applying, where tested by
means an overnight memory test.

Thanks
Troy

arch/arm/cpu/arm926ejs/davinci/lowlevel_init.S

@@ -523,9 +523,8 @@ VTPLock:
 
 	ldr	r6, DDRVTPR
 	ldr	r7, [r6]
-	and	r7, r7, $0x1f
-	and	r8, r7, $0x3e0
-	orr	r8, r7, r8
+	mov	r8, r7, LSL #32-10
+	mov	r8, r8, LSR #32-10        /* grab low 10 bits  */
 	ldr	r7, VTP_RECAL
 	orr	r8, r7, r8
 	ldr	r7, VTP_EN
@@ -644,7 +643,7 @@ VTP_LOCK_COUNT:
 VTP_MASK:
 	.word	0xffffdfff
 VTP_RECAL:
-	.word	0x40000
+	.word	0x08000
 VTP_EN:
 	.word	0x02000
 CFGTEST: