stpmic1: update register names

stpmic1: update register names

Alignment with  STPMIC1 datasheet
  s/MAIN_CONTROL_REG/MAIN_CR/g
  s/MASK_RESET_BUCK/BUCKS_MRST_CR/g
  s/MASK_RESET_LDOS/LDOS_MRST_CR/g
  s/BUCKX_CTRL_REG/BUCKX_MAIN_CR/g
  s/VREF_CTRL_REG/REFDDR_MAIN_CR/g
  s/LDOX_CTRL_REG/LDOX_MAIN_CR/g
  s/USB_CTRL_REG/BST_SW_CR/g
  s/STPMIC1_NVM_USER_STATUS_REG/STPMIC1_NVM_SR/g
  s/STPMIC1_NVM_USER_CONTROL_REG/STPMIC1_NVM_CR/g
and update all the associated defines.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>