fvp: Fix register name in 'plat_print_gic_regs' macro

The 'plat_print_gic_regs' macro was accessing the GICC_CTLR register
using the GICD_CTLR offset. This still generates the right code in
the end because GICD_CTLR == GICC_CTLR but this patch fixes it for
the logic of the code.