misc: Fix coding style for struct's opening braces

The systemc dir was not included in this fix.

First it was identified that there were only occurrences
at 0, 1, 2 and 3 levels of indentation (and a single
occurrence of 2 and 3 spaces), using:

    grep -nrE --exclude-dir=systemc \
        "^ *struct [A-Za-z].* {$" src/

Then the following commands were run to replace:

<indent level>struct X ... {

by:

<indent level>struct X ...
<indent level>{

Level 0:
    grep -nrl --exclude-dir=systemc
        "^struct [A-Za-z].* {$" src/ | \
        xargs sed -Ei \
        's/^struct ([A-Za-z].*) \{$/struct \1\n\{/g'

Level 1:
    grep -nrl --exclude-dir=systemc \
        "^    struct [A-Za-z].* {$" src/ | \
        xargs sed -Ei \
        's/^    struct ([A-Za-z].*) \{$/    struct \1\n    \{/g'

and so on.

Change-Id: I362ef58c86912dabdd272c7debb8d25d587cd455
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39017
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/riscv/plic.hh

@@ -86,7 +86,8 @@ using namespace RiscvISA;
  *   writing to M mode registers)
  */
 
-struct PlicOutput {
+struct PlicOutput
+{
   std::vector<uint32_t> maxID;
   std::vector<uint32_t> maxPriority;
 };