build: correctly report non-empty section sizes upon .o -> .init.o conversion

build: correctly report non-empty section sizes upon .o -> .init.o conversion

The originally used sed expression converted not just multiple leading
zeroes (as intended), but also trailing ones, rendering the error
message somewhat confusing. Collapse zeroes in just the one place where
we need them collapsed, and leave objdump's output as is for all other
purposes.

Fixes: 48115d14743e ("Move more kernel decompression bits to .init.* sections")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>