ANDROID: irqchip/gic-v3: fix EXPORT_SYMBOL with __init

The gic_v3_dist_init() function was recently exported to be called from
within a vendor module in https://r.android.com/3318000

. However, the
__init attribute was incorrectly kept while porting the patch into the
new branch. This triggers the following build warning:

  WARNING: modpost: vmlinux: gic_v3_dist_init: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.

Remove the __init attribute from gic_v3_dist_init() to fix it.

Cc: Nagireddy Annem <quic_nannem@quicinc.com>
Cc: Shreyas K K <quic_shrekk@quicinc.com>
Cc: Melody Olvera <quic_molvera@quicinc.com>
Cc: Unnathi Chalicheemala <quic_uchalich@quicinc.com>
Fixes: bca065e8 ("ANDROID: irqchip/irq-gic-v3: Add vendor hook for gic suspend")
Change-Id: Ibafcef50da5996be50dd905d3e2d12f2993f37fa
Signed-off-by: Carlos Llamas <cmllamas@google.com>