dt-bindings: rtc: mcp795: move to trivial-rtc

The current mcp795 bindings in text format do not support validation and
are missing the optional interrupt property that is currently supported.

Adding the missing property makes the bindings identical to the existing
trivial-rtc bindings.

Add maxim,mcp795 to the trivial-rtc bindings and delete current .txt
bindings
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230906-topic-rtc_mcp795_yaml-v3-1-5262f1b39920@gmail.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Documentation/devicetree/bindings/rtc/maxim,mcp795.txt

-* Maxim MCP795		SPI Serial Real-Time Clock
-
-Required properties:
-- compatible: Should contain "maxim,mcp795".
-- reg: SPI address for chip
-
-Example:
-	mcp795: rtc@0 {
-		compatible = "maxim,mcp795";
-		reg = <0>;
-	};

Documentation/devicetree/bindings/rtc/trivial-rtc.yaml

@@ -45,6 +45,8 @@ properties:
       - isil,isl1208
       # Intersil ISL1218 Low Power RTC with Battery Backed SRAM
       - isil,isl1218
+      # SPI-BUS INTERFACE REAL TIME CLOCK MODULE
+      - maxim,mcp795
       # Real Time Clock Module with I2C-Bus
       - microcrystal,rv3029
       # Real Time Clock