Align end of bss by 4 bytes

Most of the bss initialization loop increments 4 bytes
at a time. And the loop end is checked for an 'equal'
condition. Make the bss end address aligned by 4, so
that the loop will end as expected.

Signed-off-by: Selvamuthukumar <selva.muthukumar@e-coninfotech.com>
Signed-off-by: Wolfgang Denk <wd@denx.de>