powerpc: Fix format string warning in arch/powerpc/boot/main.c

powerpc: Fix format string warning in arch/powerpc/boot/main.c

Fix format string warning in arch/powerpc/boot/main.c.  Also correct
a typo ("uncomressed") on the same line.

 BOOTCC  arch/powerpc/boot/main.o
arch/powerpc/boot/main.c: In function 'prep_kernel':
arch/powerpc/boot/main.c:65: warning: format '%08x' expects type
'unsigned int', but argument 3 has type 'long unsigned int'

Signed-off-by: Jon Smirl <[email protected]>
Acked-by: David Gibson <[email protected]>
Signed-off-by: Paul Mackerras <[email protected]>