riscv: fix building compressed EFI image

riscv: fix building compressed EFI image

When building vmlinuz.efi with CONFIG_EFI_ZBOOT enabled, '__lshrdi3()'
is also needed to fix yet another link error observed when building
riscv32 and loongarch32 images:

riscv32-linux-gnu-ld: drivers/firmware/efi/libstub/lib-cmdline.stub.o: in function `__efistub_.L49':
__efistub_cmdline.c:(.init.text+0x202): undefined reference to `__efistub___lshrdi3'

/usr/bin/loongarch32-linux-gnu-ld: ./drivers/firmware/efi/libstub/lib-cmdline.stub.o: in function `__efistub_.L47':
__efistub_cmdline.c:(.init.text+0x26c): undefined reference to `__efistub___lshrdi3'

And since both riscv64 and loongarch64 can have CONFIG_EFI_ZBOOT but
doesn't need these library routines, rely on CONFIG_32BIT to manage
linking of lib-ashldi3.o and lib-lshrdi3.o on 32-bit variants only.

[dmantipov@yandex.ru: fix loongarch32]
Link: https://lore.kernel.org/8095016e47aceab4830c2523ce78af968ec0497e.camel@yandex.ru
Link: https://lore.kernel.org/20260519172259.908980-9-dmantipov@yandex.ru
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reported-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Closes: https://lore.kernel.org/linux-riscv/20260409050018.GA371560@inky.localdomain
Tested-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Assisted-by: Gemini:gemini-3.1-pro-preview sashiko
Tested-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andriy Shevchenko <andriy.shevchenko@intel.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>