power: rename stpmu1 to official name stpmic1

Alignment with kernel driver name & binding
introduced by https://patchwork.kernel.org/cover/10761943/
to use the final marketing name = STPMIC1.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
diff --git a/MAINTAINERS b/MAINTAINERS
index f9ee428..083bf47 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -295,7 +295,9 @@
 F:	drivers/mmc/stm32_sdmmc2.c
 F:	drivers/phy/phy-stm32-usbphyc.c
 F:	drivers/pinctrl/pinctrl_stm32.c
+F:	drivers/power/pmic/stpmic1.c
 F:	drivers/power/regulator/stm32-vrefbuf.c
+F:	drivers/power/regulator/stpmic1.c
 F:	drivers/ram/stm32mp1/
 F:	drivers/misc/stm32_rcc.c
 F:	drivers/reset/stm32-reset.c