rtc: bq4802: add error handling for devm_ioremap

rtc: bq4802: add error handling for devm_ioremap

[ Upstream commit 7874b919866ba91bac253fa219d3d4c82bb944df ]

When devm_ioremap fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling devm_ioremap.

Signed-off-by: Zhouyang Jia <jiazhouyang09@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>