[prim_lfsr] Minor lint fix

Signed-off-by: Michael Schaffner <msf@google.com>
diff --git a/hw/ip/prim/rtl/prim_lfsr.sv b/hw/ip/prim/rtl/prim_lfsr.sv
index 8139ad9..e17e112 100644
--- a/hw/ip/prim/rtl/prim_lfsr.sv
+++ b/hw/ip/prim/rtl/prim_lfsr.sv
@@ -424,7 +424,7 @@
     typedef logic [NumSboxes-1:0][LfsrIdxDw-1:0] matrix_col_t;
 
     // left-rotates a matrix column by the shift amount
-    function automatic matrix_col_t lrotcol(matrix_col_t col, int shift);
+    function automatic matrix_col_t lrotcol(matrix_col_t col, integer shift);
       matrix_col_t out;
       for (int k = 0; k < NumSboxes; k++) begin
         out[(k + shift) % NumSboxes] = col[k];