ARM: 7723/1: crypto: sha1-armv4-large.S: fix SP handling

Make the SHA1 asm code ABI conformant by making sure all stack
accesses occur above the stack pointer.

Origin:
http://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=1a9d60d2

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>