pgsql: Remove implicit cast from 'void *'

Remove implicit cast from 'void *'

Commit e2809e3a101 added code to a header which assigns a pointer
to void to a pointer to unsigned char. This causes build errors for
extensions written in C++. Fix by adding an explicit cast.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CANWCAZaCq9AHBuhs%3DMx7Gg_0Af9oRU7iAqr0itJCtfmsWwVmnQ%40mail.gmail.com
Backpatch-through: 18

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/9adb58a3ccb5ad28e773684db33ffcb1ebbd5ef1

Modified Files
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src/include/port/pg_crc32c.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)