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.

Change-Id: I7b17af50e587f07bec0e4c933e346088470c96f3
Merge pull request #150 from sandrine-bailleux/sb/fix-plat-print-gic-regs

fvp: Fix register name in 'plat_print_gic_regs' macro