x86/EFI: don't have an overly large image size

x86/EFI: don't have an overly large image size

While without debug info the difference is benign (so far), since we pad
the image to 16Mb anyway, forcing the .reloc section to a 2Mb boundary
causes subsequent .debug_* sections to go farther beyond 16Mb than
needed. There's no reason to advance . for establishing __2M_rwdata_end,
as all data past _end is of no interest at runtime anymore anyway.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>