broadcom: fix support for PTP_PEROUT_DUTY_CYCLE

broadcom: fix support for PTP_PEROUT_DUTY_CYCLE

The bcm_ptp_perout_locked() function has support for handling
PTP_PEROUT_DUTY_CYCLE, but its not listed in the supported_perout_flags.
Attempts to use the duty cycle support will be rejected since commit
d9f3e9ecc456 ("net: ptp: introduce .supported_perout_flags to
ptp_clock_info"), as this flag accidentally missed while doing the
conversion.

Drop the unnecessary supported flags check from the bcm_ptp_perout_locked()
function and correctly set the supported_perout_flags. This fixes use of
the PTP_PEROUT_DUTY_CYCLE support for the broadcom driver.

Reported-by: James Clark <jjc@jclark.com>
Fixes: d9f3e9ecc456 ("net: ptp: introduce .supported_perout_flags to ptp_clock_info")
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Tested-by: James Clark <jjc@jclark.com>
Link: https://patch.msgid.link/20250918-jk-fix-bcm-phy-supported-flags-v1-1-747b60407c9c@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>