qemu: remove unused BL32_SIZE
qemu: remove unused BL32_SIZE

I do not see any line that references BL32_SIZE.

Signed-off-by: Masahiro Yamada <378b411a8a63ecc7605ec4272234862d7781c6ae@socionext.com>

lsigithub/arm-trusted-firmware_public,lsigithub/arm-trusted-firmware_public,sbranden/arm-trusted-firmware,achingupta/arm-trusted-firmware,sbranden/arm-trusted-firmware,achingupta/arm-trusted-firmware