msm: gsi: Remove duplicate registers defines

gsi_reg.h file includes the definitions of GSI registers.
The GSI Instruction RAM registers are defined twice.
This change removes the duplication.

Change-Id: Iccd256711c28a5f4698555079a7f73ce0357a92d
Signed-off-by: Ghanim Fodi <gfodi@codeaurora.org>