All Renesas R-Car Gen2 SoCs have Timer Units (TMU).  Enable support for
them by selecting the SYS_SUPPORTS_SH_TMU gatekeeper config symbol.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/b7b9fdd6f517a8b29bf5754e7f083d3b71805130.1710865761.git.geert+renesas@glider.be