linux/export: Ensure natural alignment of kcrctab array

The ___kcrctab section holds an array of 32-bit CRC values.
Add a .balign 4 to tell the linker the correct memory alignment.

Fixes: f3304ecd

 ("linux/export: use inline assembler to populate symbol CRCs")
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>