[kmac,prim_sha2/rtl] Fix lint error in conv_endian32

One linter flags an error when `conv_data` gets declared and initialized
in one statement.  Splitting this into two statements removes the lint
error.  This shouldn't make any functional difference, but it gets those
files lint-clean without the need for a waiver.

Signed-off-by: Andreas Kurth <adk@lowrisc.org>

hw/ip/kmac/rtl/kmac_pkg.sv

@@ -417,7 +417,8 @@ package kmac_pkg;
 
   // Endian conversion functions (32-bit, 64-bit)
   function automatic logic [31:0] conv_endian32( input logic [31:0] v, input logic swap);
-    logic [31:0] conv_data = {<<8{v}};
+    logic [31:0] conv_data;
+    conv_data = {<<8{v}};
     conv_endian32 = (swap) ? conv_data : v ;
   endfunction : conv_endian32
 

hw/ip/prim/rtl/prim_sha2_pkg.sv

@@ -113,7 +113,8 @@ package prim_sha2_pkg;
   };
 
   function automatic sha_word32_t conv_endian32(input sha_word32_t v, input logic swap);
-    sha_word32_t conv_data = {<<8{v}};
+    sha_word32_t conv_data;
+    conv_data = {<<8{v}};
     conv_endian32 = (swap) ? conv_data : v;
   endfunction : conv_endian32