When relaxing, update size of symbols.

When relaxing, update size of symbols.

When performing linker relaxation, reduce the size of symbols that span
the deleted bytes.  This ensures that, for example, function symbols
will have the correct size.

bfd/ChangeLog:

	* elf32-avr.c (elf32_avr_relax_delete_bytes): During linker
	relaxation, reduce the size of symbols that span the deleted
	bytes.

ld/ChangeLog:

	* testsuite/ld-avr/relax-02.d: Update to check size of symbols has
	changed.
	* testsuite/ld-avr/relax-03.d: Likewise.