powerpc: unrel_branch_check.sh: exit silently for early errors

If we can't find the address of __end_interrupts, then we still exit
successfully as that is the current behaviour.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200811140435.20957-8-sfr@canb.auug.org.au
1 file changed