regmap: Enable REGMAP when REGMAP_SLIMBUS is enabled

regmap: Enable REGMAP when REGMAP_SLIMBUS is enabled

Invisible symbol REGMAP defaults to y when any of the REGMAP_* symbols
is enabled, effectively auto-enabling it when needed.  However,
REGMAP_SLIMBUS is missing from the list.

Currently this does not cause any issues, as all symbols selecting
REGMAP_SLIMBUS also select REGMAP and/or REGMAP_IRQ.  Add REGMAP_SLIMBUS
to the list for consistency, and to prevent any future issues.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://patch.msgid.link/47872f8f4cf613e9710963bf871c6ac7b2ce81e8.1768494166.git.geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>