nokia900.conf: migrate to newer linux-nokia900 kernel and bump PR

The new kernel is composed of the 2.6.28 kernel, last maemo PR 1.3
  patches, usb host patch,various other patches, and the necessary
  patches for booting from microsd and for compiling with gcc4.

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@no-log.org>
Acked-by: Klaus Kurzmann <mok@fluxnetz.de>

conf/machine/nokia900.conf

@@ -64,7 +64,7 @@ IMAGE_FSTYPES ?= "jffs2 tar.gz"
 
 SERIAL_CONSOLE = "115200 ttyS0"
 
-PREFERRED_PROVIDER_virtual/kernel = "linux"
+PREFERRED_PROVIDER_virtual/kernel = "linux-nokia900"
 
 #use this if you are using the nokia initfs
 ROOTFS_POSTPROCESS_COMMAND += " remove_init_link; "
@@ -76,4 +76,4 @@ module_autoload_g_ether = "g_ether"
 # Copied from include/omap3.inc (as we do not use linux-omap recipes):
 #
 # Increase this everytime you change something in the kernel
-MACHINE_KERNEL_PR = "r54"
+MACHINE_KERNEL_PR = "r55"