regmap: add missing MODULE_DESCRIPTION() macros

regmap: add missing MODULE_DESCRIPTION() macros

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-ac97.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-ram.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-raw-ram.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-slimbus.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-spmi.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-w1.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-sccb.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/base/regmap/regmap-spi-avmm.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://patch.msgid.link/20240603-md-base-regmap-v1-1-ff7a2e5f990f@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org>