drm/i915/gt: Remove {} from if-else

In accordance to Linux coding style(Documentation/process/4.Coding.rst),
remove unneeded braces from if-else block as all arms of this block
contain single statements.

Suggested-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Soumya Negi <soumya.negi97@gmail.com>
Acked-by: Karolina Stolarek <karolina.stolarek@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231026044309.17213-1-soumya.negi97@gmail.com