MAINTAINERS: gpio-brcmstb: Remove stray '>'

There is a stray '>' at the end of the mailing-list specified for the
Broadcom STB GPIO driver, remove that.

Fixes: 3b0213d5 ("gpio: Add GPIO support for Broadcom STB SoCs")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>