CPCI4052: Remove CONFIG_SYS_LONGHELP

CPCI4052: Remove CONFIG_SYS_LONGHELP

With the change to make sure that CONFIG_CMD_NET is enabled this board
no longer fits into the linker script:

powerpc-linux-ld.bfd: section .resetvec loaded at [fffffffc,ffffffff] overlaps section .u_boot_list loaded at [ffffff58,00000723]
powerpc-linux-ld.bfd: u-boot: section .resetvec lma 0xfffffffc adjusted to 0x724
powerpc-linux-ld.bfd: u-boot: section `.resetvec' can't be allocated in segment 0
LOAD: .data.init .text .rodata .reloc .data .u_boot_list .resetvec
powerpc-linux-ld.bfd: final link failed: File truncated

Drop CONFIG_SYS_LONGHELP to free up space.

Cc: Matthias Fuchs <matthias.fuchs@esd-electronics.com>
Signed-off-by: Tom Rini <trini@konsulko.com>