phy: broadcom: add missing MODULE_DESCRIPTION() macros

phy: broadcom: add missing MODULE_DESCRIPTION() macros

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/phy/broadcom/phy-bcm-ns-usb2.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/phy/broadcom/phy-bcm-ns-usb3.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240608-md-drivers-phy-broadcom-v1-1-f070f84cc3f0@quicinc.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>